C++ String Exercises: Second occurrence of a string within another string

Last update on April 11 2025 12:48:14 (UTC/GMT +8 hours)

41. Position of the Second Occurrence of a Substring

Write a C++ program that finds the position of the second occurrence of a string in another string. If the substring does not appear at least twice return -1.

Test Data:
("the qu qu", "qu") -> 7
("theququ", "qu") -> 5
("thequ", "qu") -> -1

Sample Solution:

C++ Code:

#include <bits/stdc++.h> // Include all standard libraries

using namespace std; // Using the standard namespace

// Function to find the position of the second occurrence of a substring in a string
int test(std::string text, std::string sstr) {
    // Find the position of the first occurrence of the substring in the text
    // Then, search for the substring from the index after the first occurrence
    return text.find(sstr, text.find(sstr) + sstr.size());
}

int main() {
    string text = "the qu qu"; // Initialize the input string
    string sstr = "qu"; // Initialize the substring to search
    cout << "String: " << text; // Display the original string
    cout << "\nSubstring: " << sstr; // Display the substring
    // Find and display the position of the second occurrence of the substring
    cout << "\nPosition of the second occurrence of the said substring: " << test(text, sstr);

    text = "theququ"; // Change the input string
    sstr = "qu"; // Change the substring to search
    cout << "\n\nString: " << text; // Display the modified string
    cout << "\nSubstring: " << sstr; // Display the substring
    // Find and display the position of the second occurrence of the substring
    cout << "\nPosition of the second occurrence of the said substring: " << test(text, sstr);

    text = "thequ"; // Change the input string
    sstr = "qu"; // Change the substring to search
    cout << "\n\nString: " << text; // Display the modified string
    cout << "\nSubstring: " << sstr; // Display the substring
    // Find and display the position of the second occurrence of the substring
    cout << "\nPosition of the second occurrence of the said substring: " << test(text, sstr);
}

Sample Output:

String: the qu qu
Substring: qu
Position of the second occurrence of the said substring: 7

String: theququ
Substring: qu
Position of the second occurrence of the said substring: 5

String: thequ
Substring: qu
Position of the second occurrence of the said substring: -1

Flowchart:

For more Practice: Solve these Related Problems:

• Write a C++ program to find the index of the second occurrence of a specified substring in a given string using string search functions.
• Write a C++ program that scans a string for a target substring and returns the starting index of its second appearance.
• Write a C++ program to locate the second occurrence of a substring by iterating through the string and counting matches.
• Write a C++ program that reads a string and a substring and uses the find() function twice to determine the second occurrence’s position, or returns -1 if absent.

C++ Code Editor:

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