编码给出两个不同的输出？

Question

有两类：

key.java并在test.java test.java

一个+ 5 = f的预期结果是ASCII值？它会得到输出，但是当我运行它的线：

System.out.println(k1.encode('G')); // expected output 'L' 

输出不是G加5的ascii值，它输出：

我在这里达到了极限，为什么？

key.java：

class Key{ 
    private int value; 

    Key(int value){ 
     this.value = value; 
    } 

    public char encode(char c){ 
     if (isValidKey(value) == true) { 
      if (c >= 'a' && c <= 'z'){ 
       c = (char)((c - 'a' + value) % 26 + 'a'); 
      }else if (c >= 'A' && c <= 'Z'){ 
       c = (char)((c - 'A' + value) % 26 + 'A'); 
      }else if (c >= '0' && c <= '9'){ 
       c = (char)((c - '0' + value) % 10 + '10'); 
      } else { 
       return '.'; 
      } 
      return c; 
     } 

     public char decode(char c){ 
      if (isValidKey(value) == true) { 
       if (c >= 'a' && c <= 'z'){ 
        c = (char)((c - 'a' - value) % 26 + 'a'); 
       }else if (c >= 'A' && c <= 'Z'){ 
        c = (char)((c - 'A' - value) % 26 + 'A'); 
       }else if (c >= '0' && c <= '9'){ 
        c = (char)((c - '0' - value) % 10 + '10'); 

       }else{ 
        return'.'; 
       } 

       return c; 

      } 

      public static boolean isValidKey(int value){ 
       if (value >= 0 && value <= 25){ 
        return true; 
       } else { 
        return false; 
       } 
      } 
     } 
    } 
} 

test.java：

public class Test{ 

    public static void main(String[] args) { 
     Key k1,k2; 
     k1=new Key(5); 
     k2=new Key(15); 

     String s="This is a test. Let's see if that works"; 
     String t=Cryptic.encrypt(s,k1); 
     System.out.println("Original: "+s); 
     System.out.println("Encoded with k1: "+t); 
     System.out.println("The result ddecoded with k1: "+Cryptic.decrypt(t,k1)); 

     //individual tests 

     System.out.println(Key.isValidKey(5)); // the expected output is true 

     System.out.println(Key.isValidKey(25)); // the expected output is true 
     System.out.println(Key.isValidKey(-1)); // the expected output is false 
     System.out.println(Key.isValidKey(-10)); // the expected output is false 
     System.out.println(Key.isValidKey(200)); // the expected output is false 
     System.out.println(Key.isValidKey(1)); // the expected output is true 

     Key k3= new Key(-1); 

     System.out.println(k1.encode('a')); // expected output 'f' 
     System.out.println(k2.encode('a')); // expected output 'p' 
     System.out.println(k1.encode('7')); // expected output '2' 
     System.out.println(k3.encode('a')); // expected output '.' 
     System.out.println(k3.encode('7')); // expected output '.' 

     System.out.println(k1.decode('a')); // expected output 'v' 
     System.out.println(k2.decode('a')); // expected output 'l' 
     System.out.println(k1.decode('7')); // expected output '2' 
     System.out.println(k3.decode('a')); // expected output '.' 
     System.out.println(k3.decode('7')); // expected output '.' 

     System.out.println(k1.encode('G')); // expected output 'L' 
     System.out.println(k1.decode('G')); // expected output 'B' 
     System.out.println(k1.encode('*')); // expected output '*' 

    } 

} 

Answer 1

尝试......

 public char encode(char c){ 
     if (isValidKey(value) == true) { 
      if (c >= 'a' && c <= 'z'){ 
        c = (char)((c - 'a' + value) % 26 + 'a'); 
      }else if (c >= 'A' && c <= 'Z'){ 
       c = (char)((c - 'A' + value) % 26 + 'A'); 
      }else if (c >= '0' && c <= '9'){ 
       c = (char) (c + value); 
       if(c>57) 
        c-=10; 
      } 
     } else { 
      return '.'; 
     } 
     return c; 
    }