For循環函數的參數錯誤

Question

void Image::setValues(int start_row, int end_row, int start_column, int end_column, Image & source) 
{ 
    int startPosX = start_row; 
    int startPosY = start_column; 

    for (int row = 0; startPosX < end_row; row++, startPosX++) 
     for (int col = 0; startPosY < end_column; col++, startPosY++) 
      std::cout << startPosX << " " << startPosY << std::endl; 
} 

我叫喜歡

imageTest.setValues(0, 32, 0, 32, imageTest2); 

這個功能我希望的1024套數字（32 * 32）的輸出，而不是我得到的輸出，如下圖所示。

我到底做錯了什麼？

Answer 1

您忘記在內部循環的開始初始化startPosY。

試試這個：

void Image::setValues(int start_row, int end_row, int start_column, int end_column, Image & source) 
{ 
    int startPosX = start_row; 
    int startPosY = start_column; 

    for (int row = 0; startPosX < end_row; row++, startPosX++) { 
     startPosY = start_column; 
     for (int col = 0; startPosY < end_column; col++, startPosY++) 
      std::cout << startPosX << " " << startPosY << std::endl; 
    } 
} 

Answer 2

startPosX和startPosY沒有做什麼有用的東西上面，除了使邏輯更加複雜，導致你犯錯誤。

這是更簡單，更清晰，沒有他們：

for (int row = start_row; row < end_row; row++) 
    for (int col = start_column; col < end_column; col++) 
     std::cout << row << " " << col << std::endl;