C++ Program to Implement the String Search Algorithm for Short Text Sizes

Searching for a substring within a short text is a common operation in many C++ programs, like as small-scale text editors, command line utilities, and education projects. So, in this article, we will implement a string search algorithm for short text sizes.

Importance of String Search

String search algorithms find a substring within another string. While advanced methods like KMP and Boyer-Moore are great for longer texts, a simple method like Naive search works well for short texts without added complexity.

Algorithm to Implement String Search Algorithm for Short Text Sizes

The Following is a string search algorithm ?

Begin
   Take the string and pattern as input.
   Declare the original and duplicate array with their size.
   Put the lengths of original and duplicate in len_ori and len_dupli.
   Make a loop for find out the position of the searched pattern.
   If pattern is not found, print not found otherwise print the no of instances of the searched pattern.
End

C++ Program to Implement String Search Algorithm

The following examle, searches for all occurrences of a predefined substring (pattern) within a given original string using a basic character-by-character comparison (naive string search).

#include<iostream>
#include<cstring>
using namespace std;
int main() {
   char ori[120] = "hellotutorialspoint";
   char dupli[120] = "hello";
   int i, j, k = 0;
   int len_ori = strlen(ori);
   int len_dupli = strlen(dupli);

   cout << "Original String: " << ori << endl;
   cout << "Pattern to Search: " << dupli << endl;

   for (i = 0; i <= (len_ori - len_dupli); i++) {
      for (j = 0; j < len_dupli; j++) {
         if (ori[i + j] != dupli[j]) {
            break;
         }
      }
      if (j == len_dupli) {
         k++;
         cout << "\nPattern Found at Position: " << i;
      }
   }

   if (k == 0) {
      cout << "\nNo Match Found!";
   } else {
      cout << "\nTotal Instances Found = " << k << endl;
   }
   return 0;
}

Output

When the above code is compiled and executed, it produces the following result ?

Original String: hellotutorialspoint
Pattern to Search: hello

Pattern Found at Position: 0
Total Instances Found = 1