Compound assignment operators combine an arithmetic or bitwise operation with assignment. They modify the value of the left operand using the value on the right.

#include <stdio.h>

int main()
{
    int number = 10;

    number += 5;
    printf("After += : %d\n", number);

    number -= 3;
    printf("After -= : %d\n", number);

    number *= 2;
    printf("After *= : %d\n", number);

    number /= 4;
    printf("After /= : %d\n", number);

    number %= 3;
    printf("After %%= : %d\n", number);

    return 0;
}

Example Output #

After += : 15
After -= : 12
After *= : 24
After /= : 6
After %= : 0

Explanation #

For example:

number += 5;

is equivalent to:

number = number + 5;

The common compound assignment operators are:

The operator performs the specified operation and stores the resulting value back in the left operand.