/*任意输入两个数 显示大的*/
#include<stdio.h>
main()
{
int num1,num2,num,max();//你这里应该是想声明函数，改成int max(int x,int y);

printf("input two numbers:\n");
scanf("%d%d\n",&num1 &num2);
num=max(num1,num2);
printf("max=%d\n",num);
}
max(int x,int y)//这里既然在函数里面选择了返回值，你就给出函数返回值的类型，你定义的int类型，返回也要int类型，改为int max(int x,int y).
{
int z;
if(x>y);
else
z=x;
z=y;
return(z);
}

/*任意输入两个数 显示大的*/
#include<stdio.h>
main()
{
int num1,num2,num,max();
printf("input two numbers:\n");
scanf("%d%d\n",&num1 &num2);非法指针运算
num=max(num1,num2);
printf("max=%d\n",num);
}
max(int x,int y)
{
int z;
if(x>y);
else
z=x;
z=y;
return(z);
}