C# Dealing with contradictions in string.replace

I'm getting started with C# and programming in general and I've been playing with the "if" statements, arrays and generally getting to grips with things. However, one thing that has stumped me is how you would go about performing an replace operation which is inherently contradictory.

IE: I have string "AAABBB" but I want to search through my text and replace all "A"s with "B"s and vice-versa. So my intended output would be "BBBAAA".

I'm currently trying to use string.replace and if statements but it's not working (it follows the order of the statements, so in the above examples I'd get all "A" or all "B".

Code examples:

if (string.Contains("a"));
{
    string = string.Replace("a", "b");
}

if (string.Contains("b"));
{
    string = string.Replace("b", "a");
}

Any help would be super welcome!

Jon Skeet
people
quotationmark

If you're always replacing one character with another, it's probably simplest to convert it to a char[] and go through it one character at a time, fixing each one appropriately - rather than doing "all the As" and then "all the Bs".

public static string PerformReplacements(string text)
{
    char[] chars = text.ToCharArray();
    for (int i = 0; i < chars.Length; i++)
    {
        switch (chars[i])
        {
            case 'A':
                chars[i] = 'B';
                break;
            case 'B':
                chars[i] = 'A';
                break;
        }
    }
    return new string(chars);
}

people

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