Question

class Triangulo: public Figura
{
    public:
    int x1, y1, x2, y2, x3, y3;
    void dibujar_triangulo()
    {
        cout<<"Se ha dibujado un triangulo color "<<color<<" con coordenadas "<<
        "("<<x1<<","<<y1<<")"<<endl<<"("<<x2<<","<<y2<<")"<<endl<<"("<<x3<<","<<y3<")"<<endl;
    }
};

我有这个错误：

invalid operands of types 'const char [2]' and '<unresolved overloaded function type>' to binary 'operator<<'

怎么了？

此外，这是完整的代码：

#include <conio.h>
#include <stdio.h>
#include <iostream>
#include <string>
using namespace std;

class Figura
{
    public:
    string color, nombre;
    int num_lados;
    void establecer_color(string param)
    {
        color=param;
    }
    string obtener_color()
    {
        string a;
        cin>>a;
        return a;
    }
    void establecer_lados(int param)
    {
        num_lados=param;
    }
    int obtener_lados()
    {
        int a;
        cin>>a;
        return a;
    }
};

class Circulo: public Figura
{
    public:
    int x, y;
    void dibujar_circulo()
    {
        cout<<"Se ha dibujado un circulo color "<<color<<" con centro en ("<<x<<","<<y<<")"<<endl;
    }
};

class Rectangulo: public Figura
{
    public:
    int x1, y1, x2, y2;
    void dibujar_rectangulo()
    {
        cout<<"Se ha dibujado un rectangulo color "<<color<<" con coordenadas "
        <<"("<<x1<<","<<y1<<")"<<endl<<"("<<x2<<","<<y2<<")"<<endl;
    }
};

class Triangulo: public Figura
{
    public:
    int x1, y1, x2, y2, x3, y3;
    void dibujar_triangulo()
    {
        cout<<"Se ha dibujado un triangulo color "<<color<<" con coordenadas "<<
        "("<<x1<<","<<y1<<")"<<endl<<"("<<x2<<","<<y2<<")"<<endl<<"("<<x3<<","<<y3<")"<<endl;
    }
};

int main()
{
    Circulo Cir;
    Triangulo Tri;
    Rectangulo Rec;
    int i;
    initsw:
    cout<<"Eliga:"<<endl<<"1.\tCirculo"<<endl<<"2.\tRectangulo"
    <<endl<<"3.\tTriangulo"<<endl<<"4.\tSalir"<<endl;
    cin>>i;
    cout<<"Indique el color de su figura"<<endl;
    cin>>Cir.color;
    Tri.color=Cir.color;
    Rec.color=Cir.color;
    switch (i)
    {
        case 1:
        cout<<"Por favor introduzca el centro de su circulo:(x,y)"<<endl;
        scanf("(%d,%d)",&(Cir.x),&(Cir.y));
        Cir.dibujar_circulo();
        break;
        case 2:
        cout<<"Por favor introduzca las coordenadas de su rectangulo:(x1,y1),(x2,y2)"<<endl;
        scanf("(%d,%d),(%d,%d)",&(Rec.x1),&(Rec.y1),&(Rec.x2),&(Rec.y2));
        Rec.dibujar_rectangulo();
        break;
        case 3:
        cout<<"Por favor introduzca las coordenadas de su triangulo:(x1,y1),(x2,y2),(x3,y3)"<<endl;
        scanf("(%d,%d),(%d,%d),(%d,%d)",&(Tri.x1),&(Tri.y1),&(Tri.x2),&(Tri.y2),&(Tri.x3),&(Tri.y3));
        Tri.dibujar_triangulo();
        break;
        case 4:
        goto end;
        break;
        default:
        cout<<"Error, elija otra opcion"<<endl;
        goto initsw;
    }
    end:
    return 0;
}

Answer 1

这是一个错字。您只在函数中的最后一个<之前写了")"。使用格式正确的代码可以更容易地找到一些东西：

void dibujar_triangulo()
{
    cout << "Se ha dibujado un triangulo color " << color << " con coordenadas "
         << "(" << x1 << "," << y1 << ")" << endl
         << "(" << x2 << "," << y2 << ") "<< endl
         << "(" << x3 << "," << y3 < ")" << endl;
//                                 ^^ should be <<
}

Answer 2

你错过了一个'＆lt;'来自您的大量'＆lt;＆lt;＆lt;操作符：

void dibujar_triangulo()
{
    cout << "Se ha dibujado un triangulo color " << color << " con coordenadas " <<
    "(" << x1 << "," << y1 << ")" << endl <<
    "(" << x2 << "," << y2 << ")" << endl <<
    "(" << x3 << "," << y3<")" << endl;
}

应该是：

    "(" << x3 << "," << y3 << ")" << endl;

故事的寓意是布置你的代码，以便轻松地看到规律性（和不规则性）。将所有内容压缩到一行会使其难以阅读 - 从而发现错误。在二元运算符周围使用空格会有所帮助。

注意Rob指出的endl的过度使用，我考虑写一下：

void dibujar_triangulo()
{
    cout << "Se ha dibujado un triangulo color " << color << " con coordenadas " <<
        "(" << x1 << "," << y1 << ")\n" <<
        "(" << x2 << "," << y2 << ")\n" <<
        "(" << x3 << "," << y3 << ")"   << endl;
}

或者甚至可以将坐标全部保存在一行中：

void dibujar_triangulo()
{
    cout << "Se ha dibujado un triangulo color " << color << " con coordenadas\n" <<
        "(" << x1 << "," << y1 << "), " <<
        "(" << x2 << "," << y2 << "), " <<
        "(" << x3 << "," << y3 << ")"   << endl;
}

还有几点：

您不需要#include <stdio.h>或#include <conio.h>来编译原始代码（或者，至少，我不会在MacOS X 10.6.7上使用GCC / G ++ 4.6.0）。我只是评论了这些内容。
您提到scanf()有问题。在C ++中编码时，通常不应使用<stdio.h>或scanf()系列函数。

Answer 3

<<y3<")"<<endl;

应该是

<<y3<<")"<<endl;

顺便说一句，我的一条规则是：当你的意思是endl时，永远不要说'\n'。 std::endl不只是结束一条线。它还将缓冲的输出数据刷新到操作系统，这可能意味着每次调用时都会进行昂贵的系统调用。

试试这个：

cout<<"Se ha dibujado un triangulo color " <<color<<" con coordenadas " << "(" <<x1<<","<<y1 <<")\n(" <<x2<<","<<y2 <<")\n(" <<x3<<","<<y3 <<")\n";

Answer 4

这是因为此行<之后只有一个y3：

"("<<x1<<","<<y1<<")"<<endl<<"("<<x2<<","<<y2<<")"<<endl<<"("<<x3<<","<<y3<")"<<endl;
                                                     //The error is here. ^

就像其他人所说的那样，有助于格式化代码。更可读的代码段形式可能如下所示：

class Triangulo: public Figura
{
    public:

    int x1, y1, x2, y2, x3, y3;

    void dibujar_triangulo()
    {
        cout << "Se ha dibujado un triangulo color " << color<< " con coordenadas "
             << "(" << x1 << "," << y1 << ")" << endl
             << "(" << x2 << "," << y2 << ")" << endl
             << "(" << x3 << "," << y3 << ")" << endl;
    }
};

Answer 5

这是一个错字：

... <<y3<")"<<endl;
//      ^ error here, < instead of <<

编译错误，而不是我看到的拼写错误

5 个答案: