java - 为什么 Math.abs() 返回 25 并且没有明确的返回值？

Question

我对 math.abs() 函数有点困惑。我需要调试这段代码，但不知何故找不到问题。当我尝试 println() 结果时，它总是说“没有明确的返回值”。

public class Test {

    public static void main(String[] args) {

        for (int i = 0; i < 50; i++) {
            for (int j = 0; j < 50; j++) {
                if (Math.abs(i - 25) + Math.abs(j - 25) > 25) {
                    System.out.println(" ");

                } else {
                    System.out.println("+");
                }
            }
            System.out.println();
        }

    }
}

我希望程序在 math.abs() 的结果高于 25 时输出“”，在低于 25 时输出“+”。

Answer 1

我相信Joop Eggen 的评论指出了第一个“问题”：

前两个printlns 应该是print- 没有换行符。

当你改变它时，输出变为：

                         +                        
                        +++                       
                       +++++                      
                      +++++++                     
                     +++++++++                    
                    +++++++++++                   
                   +++++++++++++                  
                  +++++++++++++++                 
                 +++++++++++++++++                
                +++++++++++++++++++               
               +++++++++++++++++++++              
              +++++++++++++++++++++++             
             +++++++++++++++++++++++++            
            +++++++++++++++++++++++++++           
           +++++++++++++++++++++++++++++          
          +++++++++++++++++++++++++++++++         
         +++++++++++++++++++++++++++++++++        
        +++++++++++++++++++++++++++++++++++       
       +++++++++++++++++++++++++++++++++++++      
      +++++++++++++++++++++++++++++++++++++++     
     +++++++++++++++++++++++++++++++++++++++++    
    +++++++++++++++++++++++++++++++++++++++++++   
   +++++++++++++++++++++++++++++++++++++++++++++  
  +++++++++++++++++++++++++++++++++++++++++++++++ 
 +++++++++++++++++++++++++++++++++++++++++++++++++
++++++++++++++++++++++++++++++++++++++++++++++++++
 +++++++++++++++++++++++++++++++++++++++++++++++++
  +++++++++++++++++++++++++++++++++++++++++++++++ 
   +++++++++++++++++++++++++++++++++++++++++++++  
    +++++++++++++++++++++++++++++++++++++++++++   
     +++++++++++++++++++++++++++++++++++++++++    
      +++++++++++++++++++++++++++++++++++++++     
       +++++++++++++++++++++++++++++++++++++      
        +++++++++++++++++++++++++++++++++++       
         +++++++++++++++++++++++++++++++++        
          +++++++++++++++++++++++++++++++         
           +++++++++++++++++++++++++++++          
            +++++++++++++++++++++++++++           
             +++++++++++++++++++++++++            
              +++++++++++++++++++++++             
               +++++++++++++++++++++              
                +++++++++++++++++++               
                 +++++++++++++++++                
                  +++++++++++++++                 
                   +++++++++++++                  
                    +++++++++++                   
                     +++++++++                    
                      +++++++                     
                       +++++                      
                        +++                       

+第二个“问题”是输出在右侧和底部缺少一个。

我会把它留给你来解决这个问题。毕竟这是你的任务，不是我们的。