c-将部分构造为参数:未知的类型名称

Question

我正试图将结构部分作为参数传入。然而，我在编译时收到了以下消息："未知类型名称'time1'"。以下是导致这些问题的代码部分：

#include <stdio.h>
struct time {
    int hour;
    int minutes;
    int seconds;
};
struct time time1;
struct time time2;
struct time elapsed;
int hourDif (time1.hour, time2.hour) {
    if (time2.hour >= time1.hour) {
        elapsed.hour = time2.hour - time1.hour;
    }
    else {
        elapsed.hour = 24 - (time1.hour - time2.hour);
    }
    return 0;
}

Answer 1

此

int hourDif (time1.hour, time2.hour)

不是函数调用，它是函数声明，在您的情况下，它也是定义，您需要的是

int hourDif (struct time time1, struct time time2)
 {
    int difference;
    difference = 0; /* some compilers might complain */
    if (time2.hour >= time1.hour)
        difference = time2.hour - time1.hour;
    else
        difference = 24 - (time1.hour - time2.hour);
    return difference;
}

然后在代码的某个地方，如果不需要全局变量，你就会有

struct time time1;
struct time time2;
/* initialize `time1' and `time2' */
int difference  = hourDiff(time1, time2);