#include <iostream>
using namespace std;

int main()
{
    const double pi=3.1415926535;  //定义pi并赋初值
    static double r,d,c,s; 
    char cm[3]={'e','x'};
    do
    {
        cout<<"请输入圆的半径：   "<<endl;
        cin>>r;
        d=2*r;  //直径
        c=pi*d;  //周长
        s=pi*r*r;  //面积
        cout<<endl<<"计算结果：";
        cout<<endl<<"直径：\t"<<d;
        cout<<endl<<"周长：\t"<<c;
        cout<<endl<<"面积：\t"<<s<<endl;
        cout<<endl<<"输入字符e或输入其他字符继续计算：  ";
        cin>>cm;
        cout<<endl; 
    }
    while (cm="ex");
    return 0;
 
}

------ Build started: Project: hg, Configuration: Debug Win32 ------
Compiling...
yu.cpp
c:\documents and settings\long\桌面\hg\hg\yu.cpp(24) : error C2440: '=' : cannot convert from 'const char [3]' to 'char [3]'
        There is no context in which this conversion is possible
Build log was saved at "file://c:\Documents and Settings\Long\桌面\hg\hg\Debug\BuildLog.htm"
hg - 1 error(s), 0 warning(s)
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========


这是怎么回事？请武林高手指教指教。

#include <iostream>
using namespace std;
 
int main()
{
    const double pi=3.1415926535;  //定义pi并赋初值
    static double r,d,c,s;
    char cm[3]={"ex"};
    do
    {
        cout<<"请输入圆的半径：   "<<endl;
        cin>>r;
        d=2*r;  //直径
        c=pi*d;  //周长
        s=pi*r*r;  //面积
        cout<<endl<<"计算结果：";
        cout<<endl<<"直径：\t"<<d;
        cout<<endl<<"周长：\t"<<c;
        cout<<endl<<"面积：\t"<<s<<endl;
        cout<<endl<<"输入字符e或输入其他字符继续计算：  ";
        cin>>cm;
        cout<<endl;
    }
    while (cm=="ex");
    return 0;
 
}
 
你的程序char cm[3] = {"ex"}; while (cm = "ex")中应是==不是= 还有endl是结束流操作符应放在不应放中间；

恩，是的
真是大意了，居然把这里忘了
还要继续努力才行

#include <iostream>
using namespace std;

int main()
{
    const double pi=3.1415926535;  //定义pi并赋初值
    static double r,d,c,s; 
    char cm[3]={'e','x'};
    do
    {
        cout<<"请输入圆的半径：   "<<endl;
        cin>>r;
        d=2*r;  //直径
        c=pi*d;  //周长
        s=pi*r*r;  //面积
        cout<<"\n"<<"计算结果：";
        cout<<"\n"<<"直径：\t"<<d;
        cout<<"\n"<<"周长：\t"<<c;
        cout<<"\n"<<"面积：\t"<<s<<endl;
        cout<<"\n"<<"输入字符ex退出或输入其他字符继续计算：  ";
        cin>>cm;
        cout<<endl; 
    }
    while (cm=="ex");
    return 0;
 
}

我在输入半径计算完之后，我输入其他的字符为什么还是会退出循环呢？
我的想法是输入ex后跳出循环退出的，但是我输入其他字符一样退出了。


[ 本帖最后由 森林一鸟 于 2009-10-18 21:53 编辑 ]

#include <iostream>
using namespace std;
 
int main()
{
    const double pi=3.1415926535;  //定义pi并赋初值
        double r=0,d,c,s;   
      char cm[3];
    do
     {
     
        cout<<"请输入圆的半径：   ";
        cin>>r;
        d=2*r;  //直径
        c=pi*d;  //周长
        s=pi*r*r;  //面积
        cout<<"\n"<<"计算结果：";
        cout<<"\n"<<"直径：\t"<<d;
        cout<<"\n"<<"周长：\t"<<c;
        cout<<"\n"<<"面积：\t"<<s<<endl;
        cout<<"\n"<<"输入字符ex退出或输入其他字符继续计算：  ";
        cin>>*cm>>*(cm+1); //cm只是代表&cm[0]
        cout<<endl;  
    }
    while (*cm!='e'||*(cm+1)!='x');
    return 0;
 
}  

谢谢楼上的