Why this program prints both true and false

Question

#include <stdio.h>

int main()
{
int a=1;
if (a--)
printf("true\n");
if (++a)
printf("false");
return 0;
}

Answer 1

a = 1;
if(a--) // here <a> is evaluated before decremented (<a> is still 1, thus considered true)
printf("true\n"); // here <a> has been decremented and becomes zero

if(++a) // here <a> is incremented and has become 1 before it is evaluated (yields true)
printf("false");

Ask away if it wasn't clear

Hth, cmiiw