Question

i want to change chars with numbers, for example: a with 1, b with 2… z with 26. so the string “hello” will be something like this: 82491513621. the first question is: how to do this with easiest way, and the second: how to do this with SWITCH statement. i tried this, but after break; it stops. thanks.

Answer 1

You need a loop, whatever you do. A simple switch is not enough.

string input = "hello";
StringBuilder output = new StringBuilder();
foreach(char c in input)
{
   output.Append((c - 'a' + 1));
}

Console.WriteLine(output);

Some explanation: since all letters have a numeric ASCII code associated in alphabetic order, it means that from any char representing a letter we can subtract ‘a’ and add 1 to get its numeric rank in the alphabet.

If using the switch statement is an absolute requirement, you will need to write a separate case for each possible value of a character:

string input = "hello";
StringBuilder output = new StringBuilder();
foreach(char c in input)
{
    switch(c)
    {
        case 'a': output.Append("1"); break;
        case 'b': output.Append("2"); break;
        // etc.
        case 'z': output.Append("26"); break;
    }             
}

Console.WriteLine(output);