TheAlgorithms-C-Plus-Plus/strings/brute_force_string_searching.cpp

#include  <iostream>
#include  <string>
#include  <vector>

using std::string;

int brute_force(string text, string pattern);
std::vector<std::vector<string>> test_set  =   {
    // {text, pattern, expected output}
     {"a", "aa", "-1"},
     {"a", "a", "0"},
     {"ba", "b", "0"},
     {"bba", "bb", "0"},
     {"bbca", "c", "2"},
     {"ab", "b", "1"}
};

int main() {
    for  (size_t i  =  0 ;  i < test_set.size();  i++) {
        int output  =  brute_force(test_set[i][0],  test_set[i][1]);
        if (std::to_string(output)  ==  test_set[i][2])
            std::cout  <<  "success\n";
        else
            std::cout  <<  "failure\n";
    }
    return 0;
}

/*
 *@description    Find a pattern in a string by comparing the pattern
 *                to every substring.
 *@param text     Any string that might contain the pattern.
 *@param pattern  String that we are searching for.
 *@return       Index where the pattern starts in the text or
 *                -1 if the pattern was not found.
 */

int brute_force(string text, string pattern) {
    size_t pat_l  =  pattern.length();
    size_t txt_l  =  text.length();
    int index  =  -1;
    if (pat_l  <=  txt_l) {
        for  (size_t i = 0;  i < txt_l-pat_l+1; i++) {
            string s  =  text.substr(i, pat_l);
            if (s  ==  pattern) {
                index  =  i;
                break;
            }
        }
    }
    return index;
}