#include<stdio.h>
int main()
{
    unsigned __int64 s=0,m=1;
    int n,i;
    scanf("%d",&n);
    if(n<=64)
    {
        for(i=1;i<=n;i++)
        {
            s+=m;
            m*=2;
        }
        printf("%I64u\n",s);
    }
    return 0;
}编译错误  说变量s没声明过  那么怎么声明

Main.cc: In function 'int main()':
Main.cc:4:19: error: expected initializer before 's'
  unsigned __int64 s=0,m=1;
                   ^
Main.cc:11:4: error: 's' was not declared in this scope
    s+=m;
    ^
Main.cc:11:7: error: 'm' was not declared in this scope
    s+=m;
       ^
Main.cc:14:20: error: 's' was not declared in this scope
   printf("%I64u\n",s);
这是结果  什么意思？