我想问一下,为什么加了if语句后,小时位就会减少啊
#include <stdio.h>
int main()
{
int hour1, minute1;
int hour2, minute2;
scanf("%d %d", &hour1, &minute1);
scanf("%d %d", &hour2, &minute2);
int ih = hour2 - hour1;
int im = minute2 - minute1;
if ( im <0 ) {
im = 60 + im;
ih --;
}
printf("时间差是%d小时%d分。\n", ih, im);
return 0;
}