帮我看看出了什么问题!!

[yaoyiping]

#include <stdio.h>
#include <stdlib.h>
interval_time(t1,t2){
int hour1;
int minute1;
int hour2;
int minute2;
t1=hour1*60+minute1;
t2=hour2*60+minute2;
if(t1<t2) printf("%d\n",t2-t1);
else
printf("%d\n",t1-t2);
}
main(){
int hour1=7;
int minute1=40;
int hour2=9;
int minute2=10;
int t1,t2;
interval_time(t1,t2);
}
我想计算两个时间的间隔,可是运行以后输出是0,请高手指教

[yxxng]

你在interval_time全部的值都没有付初值，你应该是这个意思吧！！！
main(){
int hour1=7;
int minute1=40;
int hour2=9;
int minute2=10;
int t1,t2;

t1=hour1*60+minute1;
t2=hour2*60+minute2;
if(t1<t2) printf("%d\n",t2-t1);
else
printf("%d\n",t1-t2);

}

[xiaohui_82]

#include <stdio.h>
#include <stdlib.h>
int hour1;
int minute1;
int hour2;
int minute2;
interval_time(t1,t2){
t1=hour1*60+minute1;
t2=hour2*60+minute2;
if(t1<t2) printf("%d\n",t2-t1);
else
printf("%d\n",t1-t2);
}
main(){
int t1,t2;
hour1=7;
minute1=40;
hour2=9;
minute2=10;
interval_time(t1,t2);
}
//把hour1、minute1、hour2、minute2设为全局变量，这样在子函数那里也可以用到

[greenteanet]

you should use the "hour1、minute1、hour2、minute2" as the globle variable ..