day9

《C primer plus 》

++i with i++

#include<stdio.h>
int main ()
{
    int a = 1 , b = 1 ; 
    int a1 ,b1 ;
    a1 = a++;
    b1 = ++b;
    printf("a a1 b b1 \n");
    printf("%1d %2d %1d %2d\n",a,a1,b,b1);

    return 0 ;
}

a a1 b b1 
2  1 2  2

When n++ is part of an expression, you can think of it as meaning “use n ; then increment it.” On the other hand, ++n means “increment n ; then use it.”