C++ 错误！类型为'；浮动'；和'；常量字符[2]'；到二进制'；操作员<<'；

我正在尝试制作一个程序，它相当于一个四函数计算器的两个分数。。cout语句中的每个switch情况都会出现错误。 错误是：

[Error]类型为“float”和“const char[2]”的操作数无效 二进制运算符R1>>OP>>N2>>斜杠>>D2； 如果（斜杠=='/'）） { 开关（OP） { 格“+”：

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不能检查括号：

cout<<"Addition of Given Fraction is: ("<<N1<<"/"<<D1<<") + ("<<N2<<"/"<<D2<<") = "
<<(((N1*D2)+(N2*D1))<<"/"<<(D1*D2))<<" = "<<(((N1*D2)+(N2*D1))/(D1*D2))<<endl;
  ^                               ^                     

cout中的括号不匹配

cout<<"Addition of Given Fraction is: ("<<N1<<"/"<<D1<<") + ("<<N2<<"/"<<D2<<") = "<<

(((N1*D2)+(N2*D1))<<"/"<<(D1*D2))   /*<-here*/

<<" = "<<(((N1*D2)+(N2*D1))/(D1*D2))<<endl;
                

<代码> Couuy有很多不匹配的括号。尝试在变量中存储中间值以增加代码的清晰性。<代码>主< /COD>在C++中必须有返回类型<代码> int <代码>。我检查了所有括号，它们是匹配的……看起来没有任何不匹配的。关于int，所有其他程序都没有它工作吗？不管怎样，我们都会尝试。即使使用int，仍然会给出相同的错误main@FrançoisAndrieux我为想要的界面添加了一个模型。看一看，也许你会比我更了解这个程序。：D
cout<<"Addition of Given Fraction is: ("<<N1<<"/"<<D1<<") + ("<<N2<<"/"<<D2<<") = "
<<(((N1*D2)+(N2*D1))<<"/"<<(D1*D2))<<" = "<<(((N1*D2)+(N2*D1))/(D1*D2))<<endl;
  ^                               ^                     

    case '+':
        cout<<"Addition of Given Fraction is: ("<<N1<<"/"<<D1<<") + ("<<N2<<"/"<<D2<<") = "<<((N1*D2)+(N2*D1))<<"/"<<(D1*D2)<<" = "<<(((N1*D2)+(N2*D1))/(D1*D2))<<endl;
        break;

    case '-':
        cout<<"Subtraction of Given Fraction is: ("<<N1<<"/"<<D1<<") - ("<<N2<<"/"<<D2<<") = "<<((N1*D2)-(N2*D1))<<"/"<<(D1*D2)<<" = "<<(((N1*D2)-(N2*D1))/(D1*D2))<<endl;
        break;

    case '*':
        cout<<"Multiplication of Given Fraction is: ("<<N1<<"/"<<D1<<") * ("<<N2<<"/"<<D2<<") = "<<(N1*N2)<<"/"<<(D1*D2)<<" = "<<((N1*N2)/(D1*D2))<<endl;
        break;

    case '/':
        cout<<"Division of Given Fraction is: ("<<N1<<"/"<<D1<<") / ("<<N2<<"/"<<D2<<") = "<<(N1*D2)<<"/"<<(D1*N2)<<" = "<<((N1*D2)/(D1*N2))<<endl;
        break;

cout<<"Addition of Given Fraction is: ("<<N1<<"/"<<D1<<") + ("<<N2<<"/"<<D2<<") = "<<

(((N1*D2)+(N2*D1))<<"/"<<(D1*D2))   /*<-here*/

<<" = "<<(((N1*D2)+(N2*D1))/(D1*D2))<<endl;