作为赋值左操作数所需的左值C++编译错误

Question

我试图建立一个扫雷游戏，我不断收到一个编译错误：左值操作数需要左值赋值。只在这两条线上：

#include <iostream> 
#include <ctime> 
using namespace std; 

// ------------------------------------------------------ 
// class Cell 
// represents one grid element in the Minesweeper game 
// ------------------------------------------------------ 

class Cell { 
public: 
    Cell(); 
    void print(); 
    void peek(); 
    void unittest(); 
    void setMined(bool); 
    bool getMined(); 
    void setAdj(int); 
private: 
    bool covered; 
    bool marked; 
    bool mined; 
    int adjcount; 
}; 


// ------------------------ 
// functions for class Cell 
// ------------------------ 

Cell::Cell(){ 
    covered = true; 
    marked = false; 
    mined = false; 
    adjcount = 0; 
// cout << "Creating a Cell" << endl; 
} 

void Cell::setAdj(int n){ 
    adjcount = n; 
} 

bool Cell::getMined(){ 
    return mined; 
} 

void Cell::setMined(bool b){ 
    mined = b; 
} 

void Cell::print(){ 
    if (marked) cout << " L "; 
    else { 
     if (covered) cout << " ? "; 
     else{ 
      if (mined) cout << " @ "; 
      else if (adjcount == 0) cout << " _ "; 
      else cout << " " << adjcount << " "; 
     } 
    } 
} 

void Cell::peek(){ 
    if (mined) cout << " @ "; 
    else if (adjcount == 0) cout << " _ "; 
    else cout << " " << adjcount << " "; 
} 

void Cell::unittest(){ 
    print(); cout << endl; 

    covered = false; 
    print(); cout << endl; 

    adjcount = 4; 
    print(); cout << endl; 

    mined = true; 
    print(); cout << endl; 

    covered = true; 
    print(); cout << endl; 

    marked = true; 
    print(); cout << endl; 
} 

// ------------------------------------- 
// class Board 
// this class represents a 2 dimensional 
// array of Cell objects for the game 
// of minesweeper 
//-------------------------------------- 

class Board{ 
public: 
    Board(); 
    void print(); 
    void peek(); 
    void adjacencycount(); 
    void mixMined(); 
private: 
    static const int rows = 5; 
    static const int cols = 5; 
    Cell cells [rows][cols]; 
    int mines; 
}; 

// -------------------------- 
// functions for class Board 
// -------------------------- 
Board::Board(){ 
    mines = 6; 
     for(int i = 0; i < 1 ; i++){ 
      for(int j = 0; j < mines; j++){ 
       cells[i][j].setMined(true); 
      } 
     } 
} 

void Board::mixMined(){ 
    int shuffle = 1000; 
    for(int i = 0; i < shuffle; i++){ 
     int r1 = (rand()%rows); 
     int c1 = (rand()%cols); 
     int r2 = (rand()%rows); 
     int c2 = (rand()%cols); 
     if(r1 && c1 != r2 && c2){ 
      bool temp = cells[r1][c1].getMined(); 
      cells[r1][c1].getMined() = cells[r2][c2].getMined(); 
      cells[r2][c2].getMined() = temp; 
     } 
    } 

} 

void Board::adjacencycount(){ 

    for(int i = 0; i < rows; i++){  
     for(int j = 0; j < cols; j++){ 
      if(!cells[i][j].getMined()){ 
       int count = 0; 
        if (i-1 >= 0 && j-1 >= 0 && cells[i-1][j-1].getMined()) count++; 
        if (i-1 >= 0 && cells[i-1][j].getMined()) count++; 
        if (i-1 >= 0 && j+1 <= cols-1 && cells[i-1][j+1].getMined()) count++;           
        if (j-1 >= 0 && cells[i][j-1].getMined()) count++; 
        if (j+1 <= cols-1 && cells[i][j+1].getMined()) count++;          
        if (i+1 <= rows-1 && j-1 >= 0 && cells[i+1][j-1].getMined()) count++; 
        if (i+1 <= rows-1 && cells[i+1][j].getMined()) count++; 
        if (i+1 <= rows-1 && j+1 <= cols-1 && cells[i+1][j+1].getMined()) count++; 
        cells[i][j].setAdj(count);    
        // cout << count; -- for testing purposes 
      } 
     } 
    } 
} 

void Board::print(){ 
     for (int i = 0; i < rows; i++){ 
       for (int j = 0; j < cols; j++){ 
         cells[i][j].print(); 
             } 
       cout << endl << endl; 
     } 
} 

void Board::peek(){ 
     for (int i = 0; i < rows; i++){ 
       for (int j = 0; j < cols; j++){ 
         cells[i][j].peek(); 
       } 
       cout << endl << endl; 
     } 
} 

// ------------------------- 
// main function for testing 
// ------------------------- 

int main(void) { 
    //Cell c; 
    //c.unittest(); 
    srand(time(0)); 

    Board b; 
    b.mixMined(); 
    b.adjacencycount(); 
    b.peek(); 

    return 0; 
} 

我试图让我的细胞交换，以便地雷会随机化每一个新的游戏。我周围搜查，找不到解决方案。我添加了“==”，但该功能不会做我想要的。

++编辑++对不起它没有国家要求左值，我错过了类型化

minesweeper.cpp: In member function ‘void Board::mixMined()’: 
minesweeper.cpp:130: error: lvalue required as left operand of assignment 
minesweeper.cpp:131: error: lvalue required as left operand of assignment 

这就是所发生的错误。

Answer 1

我觉得getMined()其实是这样的：

bool getMined()

所以，你想分配给rValue这是不可能的

你可能想写出这样一些功能：

void setMined(bool m)及其使用方法如下：

cells[r1][c1].setMined(cells[r2][c2].getMined());