Question

I’m facing a problem to solve this issue. I’m having a string variable, for an example

              string text="ABCD,ABCDABCD,ADCDS";

I need to search a string value like ‘BC’ into above string and find the position where “BC” occur. i.e if we search “BC” in to that string variable it will bring the output as 1,6

              0   1   2   3  4    5   6   7   8   9   10  11 12   13
            -------------------------------------------------------
            | A | B | C | D | , | A | B | C | D | , | A | D | C | S |
            -------------------------------------------------------

The problem is we cant use built in string class methods contains(), lastIndexOf(). can anyone help me to do this?

Answer 1

The problem is we cant use built in string class methods
‘contains()’,’lastIndexOf()’. can anyone help me to do this?

Then you can built your own. I assume that even Substring is forbidden.

string text="ABCD,ABCDABCD,ADCDS";
string whatToFind = "BC";

List<int> result = new List<int>();
for(int index=0; index < text.Length; index++)
{
    if(index + whatToFind.Length > text.Length)
        break;
    bool matches = true;
    for(int index2=0; index2<whatToFind.Length; index2++)
    {
        matches = text[index+index2] == whatToFind[index2];
        if(!matches)
            break;
    }
    if(matches)
        result.Add(index);
}

Here’s the running code: http://ideone.com/s7ej3