Comparing strings and get the first place where they vary from eachother

Question

I want to get the first place where 2 string vary from each other. example: for these two strings: \"AAAB\" \"AAAAC\"

I want to get the result 4.

How do i d

Answer 1

int index;
int len = Math.Min(string1.Length, string2.Length);
for (index = 0; index < len; index++)
    if (string1[index] != string2[index])
        break;

This would provide "3" for your example (zero-based indexing), so just increment the result by one.

Answer 2

string one = "AAAB";
string two = "AAAAC";

int found = -1;
int index = 0;
while (one != two && found == -1 && one.Length > index && two.Length > index)
{
    if (one[index] != two[index]) found = index;
    index++;
}