Lecture 134:- Finding Duplicates in a String

To find duplicates in a string, you can use a hash table or an array to keep track of the occurrence of each character. Here's a C++ program that demonstrates how to find and print the duplicate characters in a given string:

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#include <iostream> #include <unordered_map> #include <string> void findDuplicates(const std::string& str) {    std::unordered_map<char, int> charFrequency;    // Count the frequency of each character in the string    for (char c : str) {        charFrequency[c]++;    }    // Print the duplicate characters    bool foundDuplicates = false;    for (const auto& entry : charFrequency) {        if (entry.second > 1) {            std::cout << entry.first << " appears " << entry.second << " times." << std::endl;            foundDuplicates = true;        }    }    if (!foundDuplicates) {        std::cout << "No duplicate characters found in the string." << std::endl;    } } int main() {    std::string inputString;    std::cout << "Enter a string: ";    std::getline(std::cin, inputString);    findDuplicates(inputString);    return 0; }

In this program, we use an std::unordered_map to store the frequency of each character in the given string. The function findDuplicates calculates the frequency of each character and then prints the characters that appear more than once (i.e., the duplicates). If no duplicates are found, the program indicates that there are no duplicates in the string.

Sample Input:

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Enter a string: programming

Sample Output:

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g appears 2 times. r appears 2 times. m appears 2 times.

The program correctly identifies and prints the duplicate characters 'g', 'r', and 'm' in the input string "programming."

Keep in mind that this program is case-sensitive. If you want a case-insensitive search for duplicates, you can convert the entire string to lowercase or uppercase before performing the analysis.