请问，同学，你是要问什么 问题呢？

错误一：CompileError : 2157725.38680/Main.cc: In function ‘int main()’: 2157725.38680/Main.cc:22:21: error: ‘strcmp’ was not declared in this scope这句话是说strcmp()函数没有声明，需要在最前面声明一下
#include <string.h>
错误二：你主函数是main(){}，应该写成规范的int mian(){}
错误三：你那个类似于while (s1[i]!=*\0*)这里面不能用*\0*，要用单引号‘\0’，下面的也是要用单引号，改正之后
#include<iostream>
#include <string.h>
using namespace std;
int main()
{
char s1[80], s2[80];
int result;
cin.getline(s1, 80);
cin.getline(s2, 80);
int i = 0;
/*先把大写统一转小写*/
while (s1[i] != *\0* )
{
if ((s1[i] >= *A*) && (s1[i] <= *Z*))
s1[i] = s1[i] + 32;
i++;
}
i = 0;
while (s2[i] != *\0* )
{
if ((s2[i] >= *A*) && (s2[i] <= *Z*)) s2[i] = s2[i] + 32;
i++;
}
result = strcmp(s1, s2);
if (result == 0)
cout << "=" << endl;
else if (result>0)
cout << ">" << endl;
else
cout << "<" << endl;
return 0;
}

谢谢啦。嘿嘿

对了。我的代码本来不是**是* *的。