Compare str1 and str2
i = 0 NEW_LINE j = 0 NEW_LINE while i <= n1 - 1 and j <= n2 - 1 : NEW_LINE INDENT if ( str1 [ i ] != str2 [ j ] ) : NEW_LINE INDENT break NEW_LINE DEDENT result += str1 [ i ] NEW_LINE i += 1 NEW_LINE j += 1 NEW_LINE DEDENT return ( result ) NEW_LINE