函数参数的传递和值返回
#include <stdio.h>               #include <stdio.h>

int a(int);                      int a(int)

main()                           main()   

{                                {

int a;                            int num;

scanf("%d",&a);                  scanf("%d",&num)

printf("%d",a(a));               printf("%d",a(num));

}                                 }

int a(int a)                      int a(int num)

{                                  {
return a*a;                       return num*num;
}                                  }
      为什么a(a)就出错误改成a（num）就没有错误啊？ 不理解啊？ 有什么区别么？

原来如此~ 谢谢大家