Search for a Substring in Char Array
The C++ STL provides the std::find() function to search for a given substring in a range of values.
- If the substring is found, then find() function will return the index of the first occurrence of the given substring.
- If the substring is not found, then std::string::npos (no position) is returned which indicates that the given substring does not exist in a char array.
C++ Program to Search for a Substring in Char Array
C++
// C++ program to check if a substring is present in a char // array #include <iostream> #include <string> using namespace std; int main() { // character array char char_arr[] = "Hello, Geek!" ; // substring const char * sub_string = "Geek" ; // converting character array to string using string string char_arr_str = char_arr; // use the find method to check substring present or not if (char_arr_str.find(sub_string) != string::npos) { cout << sub_string << " substring is found in char array: " << char_arr_str << endl; } else { cout << sub_string << " substring is not found in char array: " << char_arr_str << endl; } return 0; } |
Output
Geek substring is found in char array: Hello, Geek!
Time Complexity: O(N * M), where N is the size of the char array and M is the size of the substring.
Auxiliary Space: O(1)
We can also use strstr() function to check if a substring exists in a char array or not.
How to Check if a Substring Exists in a Char Array in C++?
In C++, Char array and std::string both are used to store a sequence of characters to represent textual data. In this article, we will learn how to check if a substring exists within a char array in C++.
Example
Input: charArray[]= "Hello, Geek" subString="Geek" Output: Geek substring is found in char array: Hello, Geek!
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