What happens when assign a value to an array if the subscript exceeds the size of the array in C?
In other languages it throws an exception, does C also throw an ... |
I'd like to know how to get an array rows & columns size. For instance it would be something like this:
int matrix[][] = { { 2, 3 , 4}, { 1, ...
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What is the size of this array?
float a[10];
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I am writing a C program. In the first lines, I have
typedef float m_elem[NMAX][NMAX][3];
m_elem asa_m;
m_elem asa_mi[100];
then, some calculations. At the moment, and for each run and depending on ... |
I am experimenting a little bit with gamestudio.
I am making now a shooter game.
I have an array with the pointer's to the enemies. I want. to when an enemy is killed. ... |
Greetings
I need to calculate a first-order entropy (Markov source, like on wiki here http://en.wikipedia.org/wiki/Entropy_(information_theory) of a signal that consists of 16bit words.
This means, i must calculate how frequently ... |
I need to assign a character array containing 300000 data which are fetched from a file Numbers.dat containing 200,0000 numbers arranged in a column format(its a huge data file). The ... |
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Possible Duplicate:
Non-const declaration of array
My compiler gcc allows
int n = 5;
int a[n];
Other compiler visual c gives error. It says array of size 0 ... |
Possible Duplicate:
Sizeof an array in the C programming language?
I have been working on this for long, but can't seem to understand why this is ... |
I am trying to create an array of size 2^25 in c and then perform some elementary operations on it (memsweep function). The c code is
#include <stdio.h>
#include <time.h>
#define S (8191*4096)
main()
{
...
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When I run this program for large array sizes (e.g. 100000) the following error appears:
"General Protection" and the run in halted at line 8 (i.e. c[i]=0;).
I wondered if you help me ... |
a simple question that bugs me.
Say I have an array defined in main like so int arr[5]. Now, if I'm still inside main and I set int i = sizeof(arr)/sizeof(arr[0]) then ... |
void (*(*f[])())() defines f as an array of unspecified size, of pointers to functions that return pointers to functions that return void.
What does this means in a very very very simple ...
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I'm using getline in a while loop so that I can get all the lines one at a time; I am going to piece through each one and look at each character. However I don't know the line size and I don't know the number of lines so I have to depend on newline characters and EOF markers. However getline doesn't ... |
?Guessing it's a memory problem? Perhaps the program continually asks for more memory and waits until it gets it, (which it won't.) There could be a delay opening the file you're asking for. Have you tried and run with a smaller array? eg 260 X 1000 or even 260 X 200? Also, do you really need to store all the data ... |
@mohanphani2003 I don't see any default values in your program. You will have to clarify what you mean. 1. Variable 'arr' is defined as an automatic variable within function 'main'. Without an initializer, the initial value of an automatic variable is unpredictable; and can be expected to be different each time you run the program. 2. Had you defined 'arr' outside ... |
Hi, I have the following static arrays of different size in a class: in header: static double w2[2], x2[2]; static double w3[3], x3[3]; static double w4[4], x4[4]; in GaussLegendre.cpp: double GaussLegendre::w2[2] = {1.0, 1.0}; double GaussLegendre::x2[2] = {-0.577350269189625, 0.577350269189625}; double GaussLegendre::w3[3] = {0.555555555555556, 0.8888888888888889, 0.555555555555556}; double GaussLegendre::x3[3] = {-0.774596669241483, 0.0, 0.774596669241483}; double GaussLegendre::w4[4] = {0.347854845137453, 0.652145154862546, 0.652145154862546, 0.347854845137453}; double GaussLegendre::x4[4] = ... |
Hi. Been doing some work on my own for a while but Im struggling when it starts to get fun :) I've got my basic code finished and I even got the code to output the data to a file ready (atleast I think :). The problem is, what the software need to do is to sort the values to an ... |
Hello why am I getting 6 outputs instead of just 5 from this code? thanks #include #include using namespace std; int main(){ string a[]= { "blue", "green", "red", "black", "white" }; for(int i=0; i< (sizeof(a)-1); ++i) cout << "item [" << i << "]= " << a[i] << endl; } item [0]= blue item [1]= green item [2]= red ... |
Hi, Im trying to migrate from programming in Matlab over to C. Im trying to make a simple function to multiply one matrix by the other. I've realised that C can't determine the size of a 2d array, so im inputting the dimensions of those myself. The problem is that the output array (C=A*B) has as many rows as A and ... |
vippstar@gmail.com writes: On Sep 15, 7:55 pm, biplab Hi all, >I am using TC 3.0..there if I declare a integer array with dimension >162*219...an error msg saying that too long array is shown....what >should I do to recover from this problem??? > > char foo[162 * 219]; > Is an integer array that any C99 implementation can accept. [...] Yes, ... |
Here is a dummy program that outputs 4 instead of 200. I suspect it's because it calculates the size of pointer on 32 bit machines instead of array. Is there way to make it print 200? I need to pass the this global variable via a function call. Thanks #include #include using namespace std; char array[200]; void func1(char *str){ cout<<"func1:"< |
The class you're looking for is the std::vector, defined for your convenience in . C/C++ arrays don't do bounds checking for overhead reasons, as doing so increases the time for every array access a fair bit. Thus, they expect the programmer to handle these things for himself. It can be annoying, but there you have it. |
Hi All, I have an array x00,x01,x02,...,x0K0 x10,x11,x12,...,x1K1 .. .. .. xm0,xm1,xm2,...,xmKm m is *fixed*, each of K0, K1,...,Km is occasionally changed i.e. each row is "resized" *occasionally* each row is modified *often* by the transform algorithm does std::vector |
Hello I'm writing a small programme to look for some particular integer sets (homometric sets), and each one of this sets is a unsigned long long (e.g. {1, 2, 4, 7} --1001011=75). I need to have a very long list of sets of this kind, so I declared a #define MAXS = 397148160 static unsigned long long set[MAXS]; but MAXS seems ... |
In java, to work out the size of an array, say it was called a, you would do a.length which might return 10 as the number of elements. Is there a similar thing you can do in C++? I'd initially thought of using strlen(a) since the array I am working with is of type char. However, I found this to return ... |
Hi, I know that this issue is indeed strictly operating system dependent but I am just curious: I have a five dimensional array, whose size sums to 68 MB (almost). This array is contained by class X. When I simply attempt to create an instance of that class, I get segmentation fault. I am working on Solaris (which has 8 KB ... |
Hello friends, It seems to be quite common in libraries (e.g. GMP) to have typedefs like typedef struct { /* stuff */ } __type_struct; typedef __type_struct type_t[1]; I guess the advantage of this is that it allows type_t variables to be passed by reference without an extra level of indirection. Is this considered good C style? Are there any problems or ... |
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I am confused. Why does this not work? ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- template |
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I have a dynamically declared array of integers and i'd like to check the number of elements. For some reason, the expected sizeof(mtx)/sizeof(mtx[0]) doesn't work. I've been googling and i got a head ache more than understanding. Let me put my question this way. In Java, i'd go as mtx.length to learn the size. How can it be done _easily_ in ... |
I think the simplest way is (as you have done) to pass the size in explicitly. Another idea (which Isn't really any better a solution) is to create a structure that contains both the array and size. Then you only ned to pass one parameter, but you are still essentially doing exactly the same thing |
Hello, All! I've met the code containing this kind of structure: typedef struct cmd { unsigned int Cmd; unsigned int Code; unsigned int Data[1]; } CMD; Further in the code what programmer does is: .... #define MAX_MSGLEN 1600 CMD *tmsg; int stmsg[MAX_MSGLEN/4+1]; tmsg = (CMD_ACK *)stmsg; memset(tmsg, 0x0, MAX_MSGLEN); .... So as far as I understood, after all, we may address ... |
Hi, The following code snippet when compiled using gcc 3.3.5 creates an executable which is 6.9 KB in size. int main(){ int arr[1000000]={0}; long arr2[100000]={0}; double arr3[100000]={0}; } However int main(){ int arr[1000000]={1}; long arr2[100000]={1}; double arr3[100000]={1}; } creates an executable which is 5 MB in size. Why is there such a huge difference when we change the initialization value? In ... |
pranav.choudhary@gmail.com wrote:[color=blue] > Is it legal to keep the size of an array 0. gcc 3.4.2 did not give any > error for the declaration > > int a[0]; >[/color] This is a gcc extension (though many other compilers support it too), so the answer in general is "no, this is not legal". You have to supply -pedantic before gcc will ... |
Hi, I have a question. How can i know the size of array when it is passed to a function. For Example i have this code: #include #include void foo(int * array); int main(void) { int n=5; int array[n]; foo(array); } void foo(int * array) { /*Here how can i know the size of array without passing it explicitly*/ ... |
Hi, I am new to C++. I am reading data from file into array. The problem is , I do not know ahead how many lines the file will be. I am arbitrary assign array size with "int MAX" which is not good way of doing it, I think. could someone please sugguest/help me with better way. Thanks /////////////////////////////////////////////////////////////////////////// #include ... |
Hello, I am running my code on an embedded platform without OS. I have defined some data in a section called .eeprom. The section is defined by the linker script and starts at address zero. The symbol __eeprom_end is defined by the linker script as well, and lies at the end of this section. The address of __eeprom_end is thus equal ... |
I need the following code to return a string of character stored in array and also return the size of the array. I want to do it without using pointers and so far have the character storing working fine, it's just that I can't really think of a way to return the number of characters in the array. Anyone help me ... |
Letter user determine the size of an array? Hello all, I am working on a program called Caesar Cipher which encrypts messages by increasing each character by a value determined by the user (key). It will also roll over if the key rolls over the end of the alphabet. example) S would translate to U with a key of 2. Z ... |
It depends on whether your compiler supports C89 (the 1989 C standard) or C99 (the 1999 C standard). If you are using C99 (the 1999 C standard), then look up VLA (variable length array). Note that a VLA is not an array that magically resizes itself when you try to access an element - you have to explicitly size the array ... |
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Im creating a program that reads 2 files and concatenates them sideways. Im using fgets to read each line, one by one. some of the files im testing on have huge lines 100 million chars per line. I could use fgetc but i can imagine tht would be pretty slow and messy to write. I would guess its saleems first point: ... |
#include void matrixInit(char rowend,char columnend); char Matrix[4][4]; void masterPrint(char rowend,char columnend, char matrixToBePassed); int main() { matrixInit(4,4); masterPrint(4,4,Matrix); } void matrixInit(char rowend,char columnend) { char i=0; char j=0; for (i = 0; i < rowend; i++) { for (j = 0; j < columnend; j++) { matrix[i][j] = i + 1; } } } void masterPrint(char rowend,char columnend, char matrixToBePassed) ... |
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49. Array Size cboard.cprogramming.comThe thing is I don't know X because we will be reading in a array of numbers to GP. Basically I need a way to find the size of X from the array he reads in. I'm completely stumped and would like to know if anyone could help me with this problem. |
50. size of array cboard.cprogramming.com1. It's not part of C89 standard to use variable size arrays. To be portable to C89 compilers, you should use dynamic memory allocation. 2. You can not declare a variable size array before the size component has been assigned. Right now, when you are saying "int size;" , size contains some "random" value, and then try to create an array ... |
Hello! Im new to this site. Programming has become one of my side hobbies, even though I'm not very good at it Anyway, I have created a program that converts a text file that contains a HEX dump into a binary file. The text file looks like so...: 0xDDDDDDDD 0xDDDDDDDD 0xDDDDDDDD 0xDDDDDDDD 0xDDDDDDDD ... and so on D = predetermined hex ... |
I'm not surprised. You want 1000 * 1000000 * sizeof(float) bytes. That is about 4GB, which for a 32-bit application is "too large". If you can use a 64-bit OS and a 64-bit compiler, you could probably solve the problem that way. However, I would seriously consider your needs - because even if you manage to build an application that "works" ... |
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Hi a newbie here (just started learning C two weeks ago). I like C as a fresh start. I have been using R and Matlab for most numerical analysis. But it takes a lot of times and CPU when I use a massive data. So that motivated me to take advantage of comiplier-based languages instead of interpreter-based ones. Anyways, I would ... |
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Hi, I would definitely use some help on this: I've got a list of words in a .txt file. 1 word for 1 line. First I count the \n's to get the number of words and then I put the words to the array I defined by doing(size is number of words): Code: char chDizi[size][22]; do{ fscanf(ptDosya01,"%s",&chDizi[j]); j++; }while(j |
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Code: #include #include #include #include "structures.c" int main() { FILE *stream; if((stream=fopen("block2.dat","r"))!=NULL){ printf("Succesfully opened file\n"); } else{ printf("Failed to open file\n"); exit(1); } char number[5];char temp[10]; char num_i[5],num_j[5],num_k[5]; int j=0;int k=0;int i=0;int l,m,z,loop_var; fscanf(stream,"%s", number); num_blocks=atoi(number); printf("%i\n",num_blocks); struct block arr_blocks[num_blocks]; int no_i,no_j,no_k,total_points; for(i=0;i |
Hi, How would I use an array that doesn't have a size in its declaration? I want this array to be assigned an unknown number of values over the course of the program , but trying to declare an array of 0 size can't be done. Code: double valid_rates[VALID_PAY_RATES] = {3.50, 4.00, 4.50, 4.75, 5.00, 5.50, 5.75, 6.00}, invalid_rates[UNKNOWN_VALUE], rate; int ... |
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Code: int read_file(double **temps) { int num_temps = 0, cur_temps; FILE *filedata; double *foo; // Just a temporary variable in case realloc() fails *temps = NULL; filedata = fopen("c:\\bin.txt","rb"); if(filedata == NULL) { printf("Error opening file.\n"); } else { do { foo = realloc(*temps, sizeof(double) * (num_temps + 10)); if(!foo) { puts("Memory allocation error! Record set may be incomplete"); // Since ... |
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64. Array size cboard.cprogramming.comCode: #include int inputPhrase(char *s, int size) { int ch, i = 0; while ( i < size - 1 ) { int ch = getchar(); if ( ch == '\n' || ch == EOF ) { break; } s[i++] = ch; } s[i] = '\0'; return i; } int main(void) { char text[30]; int size = sizeof text / ... |
... //start_row, end_row,start_column,end_column are parameters to this function int source_offset=((start_row)*source_width)+start_column; int source_start_offset=source_offset; int source_height_counter=0; int source_width_counter=0; int dest_offset=0; int source_width=end_column-start_column; int source_height=end_row-start_row; //Create destination array dest = new int[source_width*source_height]; if (!dest) return; //Clear destination array memset(dest,0,source_width*source_height*sizeof(int)); //Set loop flag bool bExitLoop=false; do { dest[dest_offset]=source[source_offset]; source_offset++; dest_offset++; source_width_counter++; if (source_width_counter>source_width) { source_start_offset+=source_width; source_offset=source_start_offset; source_height_counter++; source_width_counter=0; } if (source_height_counter==source_height && source_width_counter==source_width) { bExitLoop=true; ... |
66. Array Size cboard.cprogramming.com |
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71. array size? cboard.cprogramming.com |
forgive me if I'm being stupid, but I've been using C for about a week so bear with me.... I need to use a few pretty large arrays (highest would be about 256*256*256) of floats or doubles - most smaller than that though. But I keep getting errors when I define them. If I just start a new program and put: ... |
73. size of array cboard.cprogramming.com |
74. array size?? cboard.cprogramming.com |
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When array is allocated, the system allocates memory. The call to allocate memory x number of bytes. Depending on your system, x is 32 or 64 bits. The number of elements cannot exceed the limits of a 32 or 64 bit unsigned int. Try this experiment to get a better understanding of the problem. 1. Determine the size of an array ... |
From a database I get a collection of character arrays of different sizes. I need to process some of these arrays and to do this I need to be able to determine the size of each array. If this cannot be done then I may need to export out of the database a series of defines, one for each array. This ... |
dear all, hi. i want to solve a very simple question and i wonder why i does not work! I want to create an array which i dont hard code the size and it gets its size from its elements so it means i have ar[]={1,2,3,4} instead of ar[4]={1,2,3,4}.. and I want to receive its size. what is the best solution ... |
Hi all, I am trying to execute the following code, and when i try to print the size of array it allocates more me than needed. Can some tell me the reason ... int main(int argc, char *argv[]) { int size; int arr[size]; size = 20; printf("Memory allocated to the array is: %d\n", sizeof(arr)); getch(); return 0; } I get the ... |
A 1001x1001 array takes n MB of memory where n is the sizeof individual elements in the array. That's a fairly substantial chunk. Things to try, in decreasing chance of likelihoood of success. 1) Dynamically allocate your array (eg use malloc() in C) rather than allocating it statically or as a local variable. In practice, with a fair few modern operating ... |
It depends on the compiler and available memory on the system your program runs on. The maximum value potentially supported by your compiler is the maximum value that can be stored in a size_t. That value may be obtained as SIZE_MAX (a macro in ) or equivalently, in C++ only, as std::numeric_limits::max() (in the header). The standard requires that SIZE_MAX ... |
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You can wish in one hand and crap in the other and see which one fills up first. Facts are facts until someone comes along and changes them. A modern OS with a modern compiler will use virtual memory to provide tons of storage. If the largest number your compiler will deal with is 7 1/2, however, you're still up the ... |
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That will work for a statically declared array, but it will not work for any other array. In C, arrays do not keep track of their length; an array is just a consecutive stretch of memory that you can write to and read from, nothing more. The reason Yegg's example works is that the compiler knows the size of that array, ... |
Hi. I'm writing a win32 console app and am about to implement an array of size 10,000,000 . Can someone tell me what this would do ? Would my memory be able to handle it or would it cause other variables to lose their value ? I may just end up writing the array to a text file and then just ... |
lets say you have a dynamically allocated array called darray how do u determine the size of the array? i tried: int size = sizeof(darray) * sizeof(arraytype) but the sizeof(darray) dosen't check the whole array. it only checks the sizeof of the pointer to the first element. i also tried int size = sizeof(*darray) * sizeof(arraytype) but i guess that was ... |
Hi there, does anyone knows if there is a limit to the size of an array? i need to build a 2560-by-2560 matrix using a 2d array but whenever i execute my program, it will say my project encounters a problem and cant execute. Using C languange with Visual C++ 6.0. Any feedback will be greatly appreciated. Thanks Regards Bornslippy |
First off, I store log of visitors to a site in 1 file. These sites can be up to 3,000,000 visitors per day which means 3 million lines. In the course of a month, that is about 100,000,000 (100million) lines with up to 512 characters in each line. Is there any way I can call a 2d array this big? It ... |
vector array; // add some elements to the vector for (int i = 1; i < 100; i++) { DATA_TYPE data = GetData(); array.push_back(data); } // Print the 2nd element of the array cout << array[2] << endl; // Print how many elements we have in the array. cout << array.size() << endl; |
Pardon me, vanzep, for offering a differing point of view: For one, the subscript is a constant, usually of the atomic positive limit (the max size of the default register, for example), which follows the ability of the processor to index a pointer into memory. For most Intel based machines, that's 32 bits these days. Also, there are practicle limits on ... |
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Now, if you are asking how to create an array when you won't know its size until run-time, then the answer would be to create it dynamically with malloc() or calloc() in C (and with new[] in C++). Of course, you will not be able to load it with an initializer list, but rather instead from another source (eg, from a ... |
Hi, How can i create an array which can be used throughout the program, but allow the user to affect the size. What i am doing is createing an array of a structure and i would like to get some user input to set the size. This array can then be used all over the shop, so to speak. But when ... |
i'm working with string and i have to combine them if the prefix are similar. For example suppose i have this info saved into 2d array and the number at the begining of the line it are not saved in the array since my array has 2 column then i have to check the first one 1-john bob 2-john ann 3-ann ... |
I believe if they are declared as const you can get compilers that support the latest ANSI (C99 I believe) standard. Since there are not as yet a lot of compilers that support that sort of syntax, it is best to stay away from it if you need portablity. Keep an important fact in mind: The array is created on the ... |
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#include void f(int **p, int m, int n) { int x, y; for (x = 0; x < m; ++x) { for (y = 0; y < n; ++y) { printf("%-4d", p[x][y]); } puts(""); } } int main() { int array[3][3] = { {1, 2, 3}, {4, 5, 6}, {7, 8, 9} }; int *p[3]; int x; for (x = ... |
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Hi,I am trying to write a program that requires 65536 integer array elements (locations) I am using the Turbo 3.0 compiler on Windows 98 and every time I declare the array and try to compile the program I get an error:declared Array size too large.I have tried changing the memory model in the option screen of the IDE to huge (I ... |