Question

VC++里的setw()函数总是不能用？

#include <iostream>
#include <string>
int main()
{
std::string s1("luoyesenlin"),s2("fengyujianxie");
std::cout<<s1.length()<<','<<s2.length()<<std::endl;
if(s1>s2)
std::cout<<std::setw(15)<<s1<<s1<<s1+"&"+s2<<std::endl;

return 0;
}
编译就会出现下面情况
C:\Documents and Settings\Administrator\®à­±\ds.cpp(8) : error C2039: 'setw' : is not a member of 'std'
C:\Documents and Settings\Administrator\®à­±\ds.cpp(8) : error C2065: 'setw' : undeclared identifier

Answer 1

#include<iostream>
#include<iomanip>
using namespace std;
int main()
{
string s1,s2;
char a[]="luoyesenlin",b[]="fengyujianxie";
s1=a;s2=b;
cout<<s1.length()<<','<<s2.length()<<endl;
if(strcmp(a,b)>0)
cout<<setw(15)<<s1<<s1<<s1+"&"+s2<<endl;
system("pause");
return 0;
}

给你改成这样了。。。
不知能否满意。

不行的话改成这样。
#include<iostream>
#include<iomanip>
#include<string>
using namespace std;
int main()
{
string s1="luoyesenlin",s2="fengyujianxie";
cout<<s1.length()<<','<<s2.length()<<endl;
if(s1.compare(s2)>0)
cout<<setw(15)<<s1<<s1<<s1+"&"+s2<<endl;
system("pause");
return 0;
}

OK？！

Answer 2

可以把 std:: 去掉，在 int main() 前面加上 using namespace std;

Answer 3

少了头文件，加上#include <iomanip>

Answer 4

#include <iostream>
#include <iomanip>
#include <string>
using namespace std;
这样用试试吧

Answer 5

头文件#include "iomanip.h"