如何在Java中根据特定范围的ASCII字符旋转单个字符？

Question

I am trying to come up with a function that accepts a character and a number. The number is the number of times the character should be "rotated". The accepted ASCII codes are 32 to 126.

Example of rotate = If a character "A" was rotated twice, it would end up as the character "C". If "A" was rotated three times, it would end up as the letter "D". If you look at the ASCII table:

http://www.jimprice.com/ascii-0-127.gif

Given my limit of the ASCII value being 32 to 126... ascii value 065 rotated would be ascii value 067. ascii value 124 rotated 5 times would be ascii value 34.

For example:

1. if I passed the function "!" (ASCII code 33) and the number 2, the output character should be "#" (ASCII code 35).
2. if I passed "}" (ASCII code 125) and the number 3, I should get the output character "!" (ASCII code 33).

What is the best way to accomplish this in java (can it support negative numbers for the distance to rotate instead of just positive if you want to rotate the other way around)?

Answer 1

Try something like:

static char rotate(char c, int distance) {
    assert 32 <= c && c < 127;
    if (distance < 0) distance = distance % (127 - 32) + 127 - 32;
    return (char) ((c + distance - 32) % (127 - 32) + 32);
}

Edit: Added the if (distance ... line to support negative distances.

Answer 2

Do like this

  public static char numToChar(int num,int rotate){
       int result = num+rotate;
       if(result>126){         
          result =31+(result-126);
       }
       return (char)result;
  }

System.out.println(numToChar(33,2));
System.out.println(numToChar(125,3));

Output

#
!

Answer 3

You could use this approach

public static char rotateChar(char in, int shift) {
  /* cast char to int */
  int v = (int) in;
  /* to cover wrap-around */
  v += (shift % 95);
  /* 32 - 126 = -95 */
  return (char) ((v > 126) ? v - 95 : v);
}

public static void main(String[] args) {
  System.out.printf("! + 2 = %s\n",
      String.valueOf(rotateChar('!', 2)));
  System.out.printf("} + 3 = %s\n",
      String.valueOf(rotateChar('}', 3)));
  System.out.printf("b - 1 = %s\n",
    String.valueOf(rotateChar('b', -1)));
}

! + 2 = #
} + 3 = !
b - 1 = a

Answer 4

Try This.

public static void main(String[] args) {

    String ascii;
    String rotate;
    Scanner in = new Scanner(System.in);
    System.out.println("Enter ASCII Character");
    ascii = in.nextLine();
    System.out.println("Enter Rotate value");
    rotate = in.nextLine();


    int output=(Integer.parseInt(ascii)+Integer.parseInt(rotate))% 126;

    if(output<32) output=output+32;

    System.out.println("output="+output);
    System.out.println(Character.toString ((char) output));

}