为什么我的程序停留在if循环中？

Question

我是C++新手，这就像我的第一个程序，我使用Visual C++ 2010 Express。 这是一个重量转换的东西。有一个if循环，一个else if循环和一个else。 下面是代码：

#include <iostream> 

using namespace std; 

int main() { 
float ay,bee; 
char char1; 
cout << "Welcome to the Ounce To Gram Converter" << endl << "Would you like to convert [O]unces To Grams or [G]rams To Ounces?" << endl; 
start: 
cin >> char1; 

if (char1 = "G" ||"g"){ 
cout << "How many grams would you like to convert?" << endl; 
cin >> bee; 
cout << bee << " grams is equal to: " << bee*0.035274 << " ounces." << endl; goto start; 
} 

else if (char1 = "o"||"O"){ 
cout << "How many ounces would you like to convert" << endl; 
cin >> ay; 
cout << ay << " ounces is equal to: " << ay/0.035274 << " grams." << endl; goto start; 
} 

else{ 
    cout << "Error 365457 The character you entered is to retarded to comprehend" << endl; 
goto start; 
} 

cin.ignore(); 
cin.get(); 
return 0; 
    } 

如果我进入一个 “G”，则执行此：

if (char1 = "G" ||"g"){ 
cout << "How many grams would you like to convert?" << endl; 
cin >> bee; 
cout << bee << " grams is equal to: " << bee*0.035274 << " ounces." << endl; goto start; 
} 

像它应该

但是，如果我输入一个 “O”，它执行该：

if (char1 = "G" ||"g"){ 
cout << "How many grams would you like to convert?" << endl; 
cin >> bee; 
cout << bee << " grams is equal to: " << bee*0.035274 << " ounces." << endl; goto start; 
} 

取而代之的是：

else if (char1 = "o"||"O"){ 
cout << "How many ounces would you like to convert" << endl; 
cin >> ay; 
cout << ay << " ounces is equal to: " << ay/0.035274 << " grams." << endl; goto start; 
} 

即使我把东西乱，如 “H” 发生这种情况：

if (char1 = "G" ||"g"){ 
cout << "How many grams would you like to convert?" << endl; 
cin >> bee; 
cout << bee << " grams is equal to: " << bee*0.035274 << " ounces." << endl; goto start; 
} 

取而代之的是：

else{ 
    cout << "Error 365457 The character you entered is to retarded to comprehend" << endl; 
goto start; 
} 

请告诉我，我做错了什么。

Answer 1

char1 = "o"||"O"将始终评估为真，因为"O"不为空。

你想使用char1 == 'o' || char == 'O'和类似的所有你的if语句。

请注意，=是赋值，==是相等性检查。分配时测试时使用==，分配时使用=。 C和C++允许您在检查中使用=，该检查返回赋值的值。这个值不是0，它的计算结果为true，因此你的if语句执行。