C++ Exercises: Replace all the words "dog" with "cat"

Last update on August 11 2025 12:56:55 (UTC/GMT +8 hours)

Replace "dog" with "cat"

Write a C++ program that replaces all the words "dog" with "cat".
Sample Text: The quick brown fox jumps over the lazy dog. You can assume that the number of characters in a text is less than or equal to 1000 .

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C++ Exercises: Replace all the words 'dog' with 'cat'

Sample Solution:

C++ Code:

#include <iostream>
using namespace std;

int main()
{
    string str;
    getline(cin, str); // Input text from the user

    cout << "Original text: " << str; // Display original text

    // Iterate through the string
    for (int j = 0; j < (int)str.size(); j++) {
        string key = str.substr(j, 3), repl; // Extract a substring of length 3
        if (key == "fox") { // Check if the extracted substring matches "fox"
            repl = "cat"; // If matched, replace with "cat"
            for (int k = 0; k < 3; k++) {
                str[j + k] = repl[k]; // Replace the matched substring in the original text
            }
        }
    }

    cout << "\nNew text: " << str << endl; // Display the modified text

    return 0;
}

Sample Output:

Original text: The quick brown fox jumps over the lazy dog
New text: The quick brown cat jumps over the lazy dog

Flowchart:

For more Practice: Solve these Related Problems:

Write a C++ program to replace all occurrences of the word "dog" with "cat" in a string without using STL string replace functions.
Write a C++ program that reads a text and then substitutes every instance of "dog" with "cat" using pointer manipulation.
Write a C++ program to search for the word "dog" in a text and replace it with "cat" while preserving the case of the original word.
Write a C++ program that replaces multiple occurrences of "dog" with "cat" in a paragraph and outputs the modified text line by line.

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