Why the range of signed character is -128 to 127 but not -127 to 128 ?
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Suppose I have a function
void foo(char *)
which, internally, needs to treat its input as a block of NUL-terminated bytes (say, it's a hash function on strings). I could cast the argument ... |
I have an unsigned char array with 2 elements that represents a signed integer. How can I convert these 2 bytes into a signed integer?
Edit: The unsigned char array is in ... |
I'm a little bit confused as to what an unsigned char is. A signed char is the representation of the char in bit form right? A sample problem has us rotating ... |
Obviously the standard says nothing about this, but I'm interested more from a practical/historical standpoint: did systems with non-twos-complement arithmetic use a plain char type that's unsigned? Otherwise you have potentially ... |
main()
{
unsigned x=1;
char y=-1;
if(x>y)
printf("x>y");
else
...
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Expand|Select|Wrap|Line Numbers #include "S3100.h" .. #define PACKET_LENGTH 68 //with padding bytes reserved #define CRC_LENGTH 36 ......... ......... ////IMPLEMENTATION CRC CLASS///// ======================================================================================= // Fonction: Crc32::Crc32() ... |
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The default signedness of char is not in any standard, AFAIK. I believe that's compiler dependent. The general rule is that if you care about the signedness, then declare it explicitly. That is, if you will be assigning values to it above 127, use unsigned char. If you must have negative values, use signed char. For dealing with regular, english language ... |
Hi. I've encountered a problem with rounding which I cannot resolve elegantly and I has hoping that somebody could help me out. Here's the problem description: We are given 4 numbers a, b, c, and d in the range [0..255]. These are 8-bit numbers (unsigned char), but I assume that the solution should exists for any non-negative integer. We are supposed ... |
Thanks a lot. On a related note when I am comparing two unsigned char with strcmp I get: warning: pointer targets in passing argument 2 of 'strcmp' differ in signedness Should I be worried about this? Thanks On Jul 25, 11:25*pm, Eric Sosman |
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Hi All I dont have much idea about unsigned char. I know only the range of the unsigned char i.e 0 to 255. I want to copy this long data into a unsigned char array unsigned long a=59128808 unsigned char b[20]; I want to copy using only memcpy and not through sprintf. I dont mind creating a pointer to long and ... |
AGRAJA wrote: how to convert unsigned to char? Use the cast operator: (char) Ref: http://www.thescripts.com/forum/thread477545.html > how do I print without the leading ffffff (yet the result should be char*)? Printing a pointer type requires the "%p" format specifier. On the machines I use most often, getting lots of leading 'f's is pretty much unavoidable when using %p with valid pointer ... |
static_cast only works for related user-defined types, like classes using inheritance. reinterpret_cast will cast any pointer to anty other pointer. I tried your code with reinterpret_cast and it works fine. I assume this is just a test on tyour part since C++ developers do not cast like this at any time whatsoever. |
Philip Potter wrote: .... Even twos-complement is allowed to use all-bits-one as a trap representation, and thus have range -127..127. That is debatable, and has been debated on comp.std.c. Not that I disagree; I was arguing your side in that debate. However, the other side interpreted the wording of the standard as allowing the representation that would otherwise represent negative zero ... |
Donos wrote: Hello > I have the following program, > void getValue(unsigned char* pVal) C++ (and C) pass all variables by value, however C++ has a special value called a "reference". When variables are passed by reference, assignment to them happens to the variable being passed and not the usual copy in the call. void getValue(unsigned char * & pVal) { ... |
Is there any significant difference (apart from range) in signed char and unsigned char in 'C'. wt can be an application of signed char?? It is the sign that is key. Signed means you can have a sign on it (positive/negative), unsigned you don't. Signed has sign extension abilities, unsigned doesn't. That affects how it works with operators, . Rollover appears ... |
Considering a system with 8 bit characters:: In signed char the first bit (Most significant bit) holds the signs and the remaining 7 bits hold the actual value; hence the range: -128 to +127 (max value being 2^7). In unsigned char all the 8 bits hold the value; range:0 to 255 (max value being 2^8). |
hello all, Is there a reason to prefer char over signed or unsigned char. From waht I know all strings can be coded with unsigned char while a negative number can be put in signed char. So what are the uses for plain char? Thanks to all who ansered my last post (enum). -- Email: The handle, (dot seperated), at gmail ... |
I was wondering if some one could help me. I need to put two unsigned char (8bits) near each other and make another number of it. For example: Binary 00000001 (1 dec) Binary 00000010 (2 dec) Binary result 0000000100000010 (258 dec) I would like to put them together in the way that I would not loose any bits. |
Lars Tackmann wrote: [color=blue] > Does the c standard state that for all c99 implementation char as standard > is equal unsigned char ?[/color] Not at all. It's equivalent to either signed char or unsigned char. The choice is up to the implementation. It's not _equal_ to either, though. It's a distinct type, so char *foo; unsigned char *bar = foo; ... |
hi got a little prob with data types. Im reading data from a socket in to a unsigned char buf[4096]; . Now, lets say there are 60Bytes written into the array( but it is always different). Now i want to give the bytes to a other class like: pushControlPacket(buf); but i only want to give the recieved data, not the whole ... |
Hi, I need clarification regarding signed characters in the C language. In C, char is 1 byte. So 1. Unsigned char [0 to 127] - ASCII CHARACTER SET [128 to 255] - EXTENDED CHARACTER SET 2. Signed char [-128 to 0] - ????? [0 to 127] - ASCII CHARACTER SET What does it mean for a character to be signed ? ... |
Are 3 types: signed char, char and unsigned char distinct? My compiler is treating char as signed char (i.e. it has sign, and range from -128 to 127), but the following code does not call f as I would expect: template void f(T t) { } template<> void f(char t) { } int main() { signed char ch = 0; ... |
Given signed char str_a[]="Hello, world!\n"; unsigned char str_b[]="Hello, world!\n"; what is the difference, if any, between the following two statements? printf( "%s", str_a ); printf( "%s", str_b ); If there is a difference, what is the best way to compare *str_a with 0xFF? (On my implementation, unadorned char is signed, and so I'm using if( *str_a == (signed char)0xFF ) ... ... |
ok.. If we declare a variable as char then its range would be -128 to 127.. but if we assign value >127 the variable accepts it and prints the corresponding character as per ASCII value.. So i'm confused that it won't defer whether the variable is declared as "char" or "unsigned char" |
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Doing some practice problems for a class: In this recitation you will be developing some C functions that will help get you started on the next assignment. You will be using the 8-bit floating point format given in Figure 2.34 of the text[Computer Systems 2nd Edition, Bryant and O'Hallaron], with one sign bit, 4 exp bits and 3 frac bits. In ... |
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The three types char, signed char, and unsigned char are collectively called the character types. The implementation shall define char to have the same range, representation, and behavior as either signed char or unsigned char. CHAR_MIN, defined in , will have one of the values 0 or SCHAR_MIN, and this can be used to distinguish the two options. Irrespective of the ... |
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Ah! Thanks guys. That would make sense. If the char is signed, and it's a negative number, then a bit shift converts the char to an int, and fills up the most significant byte with 1's, so that when shifting right, those 1's are pulled in. Makes sense now, but I thought I was going crazy for a bit there. Thanks. ... |
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#include ///////////////// later change the char to (int) it works fine ////////////////////////// int main() { FILE *fp; unsigned char ch; // on purpose i have made the char unsigned fp=fopen("test.txt","r"); // smaple file open if(fp==NULL) { printf("Error: file cannot be opened"); exit(1); } while((ch=fgetc(fp))!=EOF) // EOF is macors (-1) putchar((char)ch); // when u check 1 which -1 it ends up with ... |
42. unsigned char cboard.cprogramming.comThe three types char, signed char, and unsigned char are collectively called the character types. The implementation shall define char to have the same range, representation, and behavior as either signed char or unsigned char.32) 32) CHAR_MIN, defined in , will have one of the values 0 or SCHAR_MIN, and this can be used to distinguish the two options. Irrespective of ... |
unsigned char & signed char i do not understand how unsigned chars work in the code Code: #include int main(int argc,char **argv) { char input_char; char saved_char; int i,rotate,temp; int input_array[8]; int rotate_array[8]; printf("What is the input character?"); scanf("%c",&input_char); saved_char=input_char; for(i=0;i<8;i++) { if((input_char&1)==1) input_array[i]=1; else input_array[i]=0; input_char>>=1; } printf("\n\nArray is\n"); for(i=7;i>-1;i--) printf("%d",input_array[i]); printf("how many bits rotation"); scanf("%d",&rotate); for(i=0;i |
Getting a little tired of people dissing older compilers, implying they don't work well. Get off it. Old compilers DO work well and work just fine up thru XP. I have no problem with suggestions to upgrade -- it makes sense to. But stop bad-mouthing options people have that in fact do work |
When a value with integer type is converted to another integer type other than _Bool, if the value can be represented by the new type, it is unchanged. 2 Otherwise, if the new type is unsigned, the value is converted by repeatedly adding or subtracting one more than the maximum value that can be represented in the new type until the ... |
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Code: code /* prototype */ ByteType ASCIZ(ByteType *Addr); ByteType ASCIZ(ByteType *Addr) { int i, v1, v2; ByteType a1, a2, v,y; /* Convert 16-HEXA-character key to be 8-ASCII-character key. */ for (i = 0; i < 8; i++) { a1 = *Addr++; if (i == 7) a2 = *Addr; else a2 = *Addr++; /* Convert two HEXA characters into their decimal value. ... |
> unsigned char binary_type = '0x09'; Remove the single quotes. unsigned char binary_type = 0x09; You get '9', because by placing it in quotes, you're generating a long character constant, like for example 'A' is 65 in the ASCII character set. But since you only have a byte, you end up with the LSB of '0x09', which in other words is ... |
Hi all! I encountered a problem using Visual C++. my objective is to convert "char tmp" to a decimal number, but bcos char supports only -128 to 128 and i want it to be from 0 to 256, so i changed it to unsigned char instead. However, an error occurs when i use "unsigned char" with "sprintf". My code is as ... |
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Hi All, I am writing a byte stream and need to convert an int value (within range:0-255) to store in a 8-bit format(mostly in an unsigned char var). I am using cygwin g++ compiler(latest version). I thought I could use the itoa function, but it won't work with cygwin g++ compiler and also for the reason that it converts ints from ... |
Hello: I am working a biometric project, my problem is now that I need save the native finger data format in SQl Server Data Base format compatible (varchar). First It is declarate like unsigned char, then is copy through memcpy to other struct unsigned char... See the code: #define AC__UCHAR unsigned char static AC__UCHAR temp1[256]; static AC__UCHAR fpData[512]; int storeFingerPrintData() { ... |
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int main() { int a = 12345; int x; x = bcd(a); cout << x <= 1; --i) { totvalue = s[i] - '0'; start changing decimal number into binary code... } return totvalue; ... |
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Hello all, I've heard that it's good practice to always declare char variables as signed or unsigned. Could anyone comment? Is it worth it? In addition, under what circumstances should one declare one or the other? I note that when I tried to compile a program under Linux with all unsigned chars, I got errors when using printf: "warning: pointer ... |