Reading and writing files in C++ - Mini Project: Build & Apply

Reading and writing files

📖 Scenario: You are working on a simple program that saves and reads a list of favorite fruits to and from a file. This is useful when you want to keep your data even after the program stops running.

🎯 Goal: Build a C++ program that writes a list of fruits to a file and then reads the fruits back from the file to display them.

📋 What You'll Learn

Create a vector of strings with exact fruit names

Create a string variable for the filename

Write the fruits to the file using ofstream

Read the fruits from the file using ifstream

Print each fruit read from the file

💡 Why This Matters

🌍 Real World

Reading and writing files is a basic skill used in many programs to save user data, settings, or logs so the information is not lost when the program closes.

💼 Career

Many software jobs require handling files for data storage, configuration, or communication between programs. Knowing how to read and write files is essential.

1

Create the list of fruits

Create a std::vector<std::string> called fruits with these exact entries: "Apple", "Banana", "Cherry", "Date", "Elderberry".

C++

#include 
#include 
#include 
#include 

int main() {

    // Create the vector fruits with the given fruit names
    // Your code here

    return 0;
}

Need a hint?

Use curly braces {} to list the fruit names inside the vector.

2

Set the filename

Create a std::string variable called filename and set it to "fruits.txt".

C++

#include 
#include 
#include 
#include 

int main() {

    std::vector fruits = {"Apple", "Banana", "Cherry", "Date", "Elderberry"};

    // Create the filename string
    // Your code here

    return 0;
}

Need a hint?

Use double quotes "" to set the filename string.

3

Write fruits to the file

Use std::ofstream to open the file with the name filename. Then use a for loop with variable fruit to write each fruit from fruits to the file, each on its own line. Close the file after writing.

C++

#include 
#include 
#include 
#include 

int main() {

    std::vector fruits = {"Apple", "Banana", "Cherry", "Date", "Elderberry"};

    std::string filename = "fruits.txt";

    // Open the file for writing and write each fruit
    // Your code here

    return 0;
}

Need a hint?

Use std::ofstream to open the file and the insertion operator << to write each fruit followed by a newline.

4

Read fruits from the file and print

Use std::ifstream to open the file with the name filename. Use a std::string variable called line. Use a while loop with std::getline to read each line from the file into line. Inside the loop, print the line using std::cout. Close the file after reading.

C++

#include 
#include 
#include 
#include 

int main() {

    std::vector fruits = {"Apple", "Banana", "Cherry", "Date", "Elderberry"};

    std::string filename = "fruits.txt";

    std::ofstream outFile(filename);
    for (const std::string& fruit : fruits) {
        outFile << fruit << "\n";
    }
    outFile.close();

    // Open the file for reading and print each line
    // Your code here

    return 0;
}

Need a hint?

Use std::getline inside a while loop to read each line and print it.