// c++ code template
#include <iostream.h>
void main()
{
float num1;
float num2;
char op;
float ans;
cout << "Please enter a number: " ;
cin >> num1;
cout << "please entet another nunber: " ;
cin >> num2;
cout << "press A to add the two numbers."
<< endl
<< "press S to subtract the two numbers."
<< endl
<< "press M to multiply the two numbers."
<< endl
<< "press D to divide the two numbers."
<< endl;
cin.ignore();
cin >> op;
if (op == 65)
{
ans = num1 + num2;
cout << "The answet is " << ans << endl;
}
if (op == 83)
{
ans = num1 - num2;
cout << "The answet is " << ans << endl;
}
if (op == 77)
{
ans = num1 * num2;
cout << "The answet is " << ans << endl;
}
if (op == 68)
{
ans = num1 / num2;
cout << "The answet is: " << ans << endl;
}
if (op != 65 && op !=83 && op != 77 && op != 68)
{
cout << "No valid operation was chosen!" << endl;
}
}
没有输出最后的结果！？

[此贴子已经被作者于2007-3-8 10:09:03编辑过]

if (op != 65 && op !=83 && op != 77 && op != 68)
如果还是不行的话你在 cin >> op;之前加个 cin.ignore();试试

显示是这样 我照你给的方法改过来了

首先你程序的op那是字符型的你做if判断不能按你的意思正确判断,把op改成int型.另外你是不是没看程序只是复制粘贴的,你输入23,和输入123后下面是正确的输出啊你程序就是这么设定的,你想输出计算结果后面还要继续输入op的值才能判断你要用哪个输入符.
#include <iostream.h>
void main()
{
float num1;
float num2;
int op;
float ans;
cout << "Please enter a number: " ;
cin >> num1;
cout << "please entet another nunber: " ;
cin >> num2;
cout << "press A to add the two numbers."
<< endl
<< "press S to subtract the two numbers."
<< endl
<< "press M to multiply the two numbers."
<< endl
<< "press D to divide the two numbers."
<< endl;
cin >> op;
if (op == 65)
{
ans = num1 + num2;
cout << "The answet is " << ans << endl;
}
if (op == 83)
{
ans = num1 - num2;
cout << "The answet is " << ans << endl;
}
if (op == 77)
{
ans = num1 * num2;
cout << "The answet is " << ans << endl;
}
if (op == 68)
{
ans = num1 / num2;
cout << "The answet is: " << ans << endl;
}
if (op != 65 && op !=83 && op != 77 && op != 68)
{
cout << "No valid operation was chosen!" << endl;
}
}

[此贴子已经被作者于2007-3-8 10:22:16编辑过]

哦哦~
知道了~ 待研究研究！

接收换行符,使得不会赋值给op

嘿嘿

// c++ code template
#include <iostream.h>
void main()
{
float num1;
float num2;
char op;
float ans;
cout << "press A to add the two numbers."
<< endl
<< "press S to subtract the two numbers."
<< endl
<< "press M to multiply the two numbers."
<< endl
<< "press D to divide the two numbers."
<< endl;
// cin.ignore();注意这里,如果保留将会有一个输入被忽略,不会的正确的结果.

cout << "Please enter a number: " ;
cin >> num1;
cout << "please entet another nunber: " ;
cin >> num2;
cin >> op;
if (op == 65+32)
{
ans = num1 + num2;
cout << "The answet is " << ans << endl;
}
if (op == 83+32)
{
ans = num1 - num2;
cout << "The answet is " << ans << endl;
}
if (op == 77+32)
{
ans = num1 * num2;
cout << "The answet is " << ans << endl;
}
if (op == 68+32)
{
ans = num1 / num2;
cout << "The answet is: " << ans << endl;
}
if (op != 65 && op !=83 && op != 77 && op != 68)
{
cout << "No valid operation was chosen!" << endl;
}
}
另外,要注意ASCII吗,我觉得应该用小写的,这更符合习惯.

我用你贴得代码在我机器上运行很好啊！！没有什么问题。。。我用的是VC6.0

VC6.0 没问题