错误！ 'float' 和 'const char [2]' 类型的无效操作数转换为二进制 'operator<<'

Question

我正在尝试编写一个程序，它相当于一个四函数计算器的两个分数。错误出现在 cout 语句中的每个 switch 情况中。错误是：

[Error] invalid operands of types 'float' and 'const char [2]' to binary 'operator<<'

我尝试使用谷歌搜索，但没有找到任何结果，但我确实发现了同样的错误，但使用的是 int 而不是 float。不幸的是，他犯了一个明显的错误，他甚至没有使用 cout 语句并将 << 运算符放在最后。另外，我尝试添加更多括号来指定首先执行哪些算术运算，但没有效果。

#include <iostream>
#include <conio.h>

using namespace std;

main()
{   //This Program is an equivalent of a four function calculator for fraction
    float N1, D1, N2, D2;
    char OP, slash;
    system("cls");
    
    cout<<"Hint: Enter Both Fractions with Operator in between; 1/2 + 6/3";
    cout<<"\nEnter Fractionaly Binary Operation: ";
    cin>>N1>>slash>>D1>>OP>>N2>>slash>>D2;

    if(slash=='/')
    {
        switch(OP) 
        {
            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;

            default:
                cout<<"INVALID OPERATOR!";
                getch();
                system("cls");
                return(0);
        }
    }
    else
    {
        cout<<"INVALID INPUT!";
        getch();
        system("cls");
        return(0);
    }
    
    
    getch();
    system("cls");
    return(0);
}

同样的错误在下面几行..

                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;

我必须将此作为作业提交。

这是我想要的界面。注意：这里是用cout语句做的，后台没有计算。

Answer 1

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;
  ^                               ^

试试这个：

    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;

Answer 2

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;

(((N1*D2)+(N2*D1))<<"/"<<(D1*D2))在一个街区内。

错误！ 'float' 和 'const char [2]' 类型的无效操作数转换为二进制 'operator<<'

ERROR! invalid operands of types 'float' and 'const char [2]' to binary 'operator<<'

c++

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