c - 体系结构 x86_64 的 undefined symbol 在 C 中意味着什么？

Question

这是我的代码。

#include <stdio.h>

int main(){
int first;
int second;
int third;
float average=0.0;

    printf ("This program will find the average of 3 numbers.\n");
    delay(1000);
    printf ("Type the first number.\n");
    scanf ("%d", &first);
    printf ("Type the second number.\n");
    scanf ("%d", &second);
    printf ("Type the third number.\n");
    scanf ("%d", &third);
    average = (first+second+third)/2.0;
    printf ("The average of %d, %d, and %d is %.3f\n", first, second, third, average);

return (0);
}

当我用gcc编译的时候说

Undefined symbols for architecture x86_64:
  "_delay", referenced from:
      _main in cc62F0GD.o
ld: symbol(s) not found for architecture x86_64
collect2: ld returned 1 exit status

我是编码初学者。这是什么意思，我该如何解决？

Answer 1

编辑

由于代码是在 linux 环境中运行的，因此您可以使用 sleep 而不是 delay。头文件是unistd.h。