In C, ++ and -- operators are called increment and decrement operators. They are unary operators needing only one operand. Hence ++ as well as -- operator can appear before or after the operand with same effect.
That means both i++ and ++i will be equivalent.
i=5;
i++;
printf("%d",i);and
i=5
++i;
printf("%d",i);both will make i=6.
However, when increment expression is used along with assignment operator, then operator precedence will come into picture.
i=5; j=i++;
In this case, precedence of = is higher than postfix ++. So, value of i is assigned to i before incrementing i. Here j becomes 5 and i becomes 6.
i=5; j=++i;
In this case, precedence of prefix ++ is more than = operator. So i will increment first and the incremented value is assigned to j Here i and j both become 6.
#include <stdio.h>
int main() {
int i=5,j;
j=i++;
printf ("\nafter postfix increment i=%d j=%d", i,j);
i=5;
j=++i;
printf ("\n after prefix increment i=%d j=%d",i,j);
return 0;
}The output is
after postfix increment i=6 j=5 after prefix increment i=6 j=6