c - 静态声明遵循非静态声明错误消息

Question

编译器给我一条错误消息

line 20: "static declaration of ‘timeDifference’ follows non-static declaration"

然后是另一个

line 12: "previous declaration of ‘timeDifference’ was here"

我知道这与我的函数“timeDifference”有关。这是我的代码:

#include <stdio.h>

struct time
{
    int hours;
    int minutes;
    int seconds;
};

main ()
{
    int timeDifference (struct time  diff);

    struct time  early, late, difference;

    printf ("Enter Start Time hh:mm:ss ");

    scanf  ("%d:%d:%d", &early.hours, &early.minutes, &early.seconds);

    printf ("Enter End Time hh:mm:ss ");

    scanf  ("%d:%d:%d", &late.hours, &late.minutes, &late.seconds);

    int timeDifference (struct time  diff)
    {
            if (late.seconds < early.seconds)
            late.seconds += 60;
            late.minutes -= 1;
            if (late.minutes < early.minutes)
            late.minutes += 60;
            late.hours -= 1;
            if (late.hours < early.hours)
            late.hours += 24;

            diff.seconds = late.seconds - early.seconds;
            diff.minutes = late.minutes - early.minutes;
            diff.hours   = late.hours   - early.hours;
    }

    return 0;
}

Answer 1

在 C 语言中，一个函数不能包含在另一个函数中。第 12 行的 timeDifference 声明以及从第 20 行开始的函数本身(定义)需要移至 main()函数。