Installation and Configuration
Programming Methodology

Find and Replace a Word in a File Using C++

In this exercise, you will create a C++ program that searches for a specific word in a text file and replaces it with another word. This task will help you strengthen your understanding of file handling and string manipulation in C++. The program will prompt the user to enter the name of the file, the word to be searched, and the replacement word. Then, it will read the file content, perform the replacement, and write the updated content back to the same file or a new file. This kind of operation is commonly used in text processing tools and document editors.

Group

File Management in C++

Objective

1. Ask the user to enter the file name, the word to search for, and the replacement word.
2. Open the file using `ifstream` and read all content line by line.
3. Replace every occurrence of the target word with the replacement word.
4. Write the updated content to the same file or a different file using `ofstream`.
5. Display a message confirming the replacements were made.

Create a program that searches for a word in a file and replaces it.

Example C++ Exercise

 Copy C++ Code 
#include <iostream>         // Include for input and output
#include <fstream>          // Include for file handling
#include <string>           // Include for string manipulation

using namespace std;

int main() {
    string fileName;         // Variable to store file name
    string wordToFind;       // Word to search in the file
    string wordToReplace;    // Word to replace with

    // Ask user for file name and the words to find and replace
    cout << "Enter the file name: ";
    cin >> fileName;
    cout << "Enter the word to find: ";
    cin >> wordToFind;
    cout << "Enter the word to replace it with: ";
    cin >> wordToReplace;

    ifstream inFile(fileName);   // Open the file for reading

    // Check if the file opened successfully
    if (!inFile) {
        cout << "Error: Cannot open the file." << endl;
        return 1;   // Exit with error
    }

    string line;                // Variable to store each line
    string fileContent = "";    // String to hold the full content

    // Read the file line by line
    while (getline(inFile, line)) {
        size_t pos = 0;

        // Replace all occurrences of the word in the current line
        while ((pos = line.find(wordToFind, pos)) != string::npos) {
            line.replace(pos, wordToFind.length(), wordToReplace);
            pos += wordToReplace.length(); // Move past the replaced word
        }

        fileContent += line + "\n"; // Append modified line to the full content
    }

    inFile.close();  // Close the input file

    ofstream outFile(fileName); // Reopen the file for writing (overwriting)

    // Write the modified content back into the file
    outFile << fileContent;
    outFile.close();  // Close the output file

    // Confirm to the user
    cout << "All occurrences of '" << wordToFind << "' have been replaced with '" << wordToReplace << "'." << endl;

    return 0;   // End of program
}

 Output

Enter the file name: notes.txt
Enter the word to find: hello
Enter the word to replace it with: hi
All occurrences of 'hello' have been replaced with 'hi'.

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