Learn C - C Arithmetic Operators
C supports the four basic arithmetic operations such as addition, subtraction, multiplication, and division.
An arithmetic statement is of the following form:
variable_name = arithmetic_expression;
The arithmetic expression on the right of the = operator specifies a calculation using values stored in variables or explicit numbers that are combined using arithmetic operators such as addition (+), subtraction (-), multiplication (*), and division (/).
total_count = birds + tigers + pigs + others;
The following table lists the Basic Arithmetic Operators.
| Operator | Action |
|---|---|
| + | Addition |
| - | Subtraction |
| * | Multiplication |
| / | Division |
| % | Modulus |
The values that an operator is applied to are called operands.
An operator that requires two operands, such
as %, is called a binary operator.
An operator that applies to a single value is called a unary operator. Thus - is a binary operator in the expression a - b and a unary operator in the expression -data.
#include <stdio.h>
//from www. ja v a2 s . c om
int main(void)
{
int cakes = 5;
int CALORIES = 125; // Calories per cookie
int total_eaten = 0;
int eaten = 2;
cakes = cakes - eaten;
total_eaten = total_eaten + eaten;
printf("I have eaten %d cakes. There are %d cakes left", eaten, cakes);
eaten = 3; // New value for cakes eaten
cakes = cakes - eaten;
total_eaten = total_eaten + eaten;
printf("\nI have eaten %d more. Now there are %d cakes left\n", eaten, cakes);
printf("\nTotal energy consumed is %d calories.\n", total_eaten * CALORIES);
return 0;
}
The code above generates the following result.
Example
The following is the code illustration for basic arithmetic:
#include <stdio.h>
/*from w w w . j a va2 s. com*/
int main() {
int a,b,c;
a = 10;
b = 6;
c = a + b;
printf("%d + %d = %d\n",a,b,c);
c = a - b;
printf("%d - %d = %d\n",a,b,c);
c = a * b;
printf("%d * %d = %d\n",a,b,c);
float d = a / b;
printf("%d / %d = % .2f\n",a,b,d);
float e =(float)a / b;
printf("%d / %d = % .2f\n",a,b,e);
return 0;
}
The code above generates the following result.
Division and the Modulus Operator
Suppose you have 45 cakes and a group of seven children.
You'll divide the cakes equally among the children and work out how many each child has.
Then you'll work out how many cakes are left over.
#include <stdio.h>
/* www.ja va 2 s . c om*/
int main(void) {
int cakes = 45;
int children = 7;
int cakes_per_child = 0;
int cakes_left_over = 0;
// Calculate how many cakes each child gets when they are divided up
cakes_per_child = cakes/children;
printf("%d children and %d cakes\n", children, cakes);
printf("each child has %d cakes.\n", cakes_per_child);
cakes_left_over = cakes%children;
printf("%d cakes left over.\n", cakes_left_over);
return 0;
}
The code above generates the following result.
op= Form of Assignment
C is a very concise language and it provides you with abbreviated ways of specifying some operations.
Consider the following statement:
number = number + 10;
This sort of assignment has a shorthand version:
number += 10;
The += operator after the variable name is one example of a family of op= operators.
This statement has exactly the same effect as the previous one, and it saves a bit of typing.
The op in op= can be any of these arithmetic operators:
+ - * / %
If you suppose number has the value 10, you can write the following statements:
number *= 3; // number will be set to number*3 which is 30 number /= 3; // number will be set to number/3 which is 3 number %= 3; // number will be set to number%3 which is 1
The op in op= can also be a few other operators that you haven't encountered yet:
<< >> & ^ |
The op= set of operators always works the same way.
The general form of statements using op=:
lhs op= rhs;
where rhs represents any expression on the right-hand side of the op= operator.
The effect is the same as the following statement form:
lhs = lhs op (rhs);
First, consider this statement:
variable *= 12;
This is the same as:
variable = variable * 12;
You now have two different ways of incrementing an integer variable by 1.
Both of the following statements increment count by 1:
count = count + 1; count += 1;
Because the op in op= applies to the result of evaluating the rhs expression, the statement:
a /= b + 1;
is the same as
a = a/(b + 1);
divisions we have known
#include <stdio.h>
int main(void)
{ /*from w w w. j av a 2s . com*/
printf("integer division: 5/4 is %d \n", 5/4);
printf("integer division: 6/3 is %d \n", 6/3);
printf("integer division: 7/4 is %d \n", 7/4);
printf("floating division: 7./4. is %1.2f \n", 7./4.);
printf("mixed division: 7./4 is %1.2f \n", 7./4);
return 0;
}
The code above generates the following result.
Example 2
The following code shows how to write a simple calculator that can add, subtract, multiply, divide, and find the remainder when one number is divided by another.
#include <stdio.h>
/*from www .j a va 2s .c o m*/
int main(void) {
double number1 = 0.0; //* First operand value a decimal number *//
double number2 = 0.0; //* Second operand value a decimal number *//
char operation = 0; //* Operation - must be +, -, *, /, or % *//
printf("\nEnter the calculation(eg. 1+2)\n");
scanf("%lf %c %lf", &number1, &operation, &number2);
switch(operation)
{
case '+': // No checks necessary for add
printf("= %lf\n", number1 + number2);
break;
case '-': // No checks necessary for subtract
printf("= %lf\n", number1 - number2);
break;
case '*': // No checks necessary for multiply
printf("= %lf\n", number1 * number2);
break;
case '/':
if(number2 == 0) // Check second operand for zero
printf("\n\n\aDivision by zero error!\n");
else
printf("= %lf\n", number1 / number2);
break;
case '%': // Check second operand for zero
if((long)number2 == 0)
printf("\n\n\aDivision by zero error!\n");
else
printf("= %ld\n", (long)number1 % (long)number2);
break;
default: // Operation is invalid if we get to here
printf("\n\n\aIllegal operation!\n");
break;
}
return 0;
}
The code above generates the following result.
