dateDiff是C语言库函数吗

Question

报错[Error] ld returned 1 exit status
源代码
#include
struct date
{
int month;
int day;
};
int main()
{
int dateDiff(struct date date1,struct date date2);
struct date date1,date2;
int x;
scanf("%d:%d",&date1.month,&date1.day);
scanf("%d:%d",&date2.month,&date2.day);
x=dateDiff(date1,date2);
if(x<0)
{
printf("Duang\n");
}
else
{
printf("%d\n",x);
}
return 0;
}

Answer 1

没这个函数，而且你自己都定义一次了就算有肯定也不会用。