Question

Do you have any idea to add parentheses to math operation string automatically and randomly?

For example.

A given operation string:

57 x 40 – 14 + 84 ÷ 19

I need to auto add parentheses randomly in above string.

so it becomes:

(57 x 40) – 14 + (84 ÷ 19) or

(57 x 40) – (14 + 84 ÷ 19) or

57 x (40 – 14) + (84 ÷ 19) or

57 x (40 – 14 + 84 ÷ 19) or

57 x (40 – (14 + 84) ÷ 19)

It really appreciated for the help!!

Mick,

Answer 1

I assumed three things:

1. There is always space char between number and operator
2. All numbers are integers (you can easily change that to other types)
3. Everything that is not number is operator

Example in C#:

Math m = new Math(); 
string p = m.DoStuff("57 x 40 - 14 + 84 ÷ 19");
Console.WriteLine(p);

class Math
{       
    internal string DoStuff(string p)
    {
        bool isParOpen = false;
        Random rnd = new Random();
        StringBuilder result = new StringBuilder();
        int i;

        string[] stack = p.Split(' ');
        foreach (var item in stack)
        {
            if (int.TryParse(item, out i))
            {
                if (rnd.Next(2) == 1)
                {
                    result.Append(isParOpen ? string.Format("{0}) ", item) : string.Format("({0} ", item));
                    isParOpen = !isParOpen;
                }
                else
                {
                    result.Append(item).Append(" ");
                }
            }
            else
            {
                result.Append(item).Append(" ");
            }
        }

        if (isParOpen)
        {
            result.Append(")");
        }

        return result.ToString();
    }
}