Small Steps IV — Saving and Loading

Reading values back from a file

Read values back from a file.

What you will learn

Opening a saved file retrieves values from a previous run. A path identifies the file's location.

Try it

void small_main()
{
    File file;

    file.open("score.txt");

    String name = file.input();
    int score = file.input_int();

    file.close();

    print(name, "'s score: ", score);
}

First create score.txt with the previous lesson. Save this source in the same folder to read the same file.

open's default mode is reading. Input reads the first line as a string; input_int reads the second as an integer. Check for Alex's score: 1200. If an error occurs, check the file location and line contents.

Exercise

Save 950 in highscore.txt, reopen it, read it as an int, and print it.

void small_main()
{
    File file;

    // Save 950, close the file, then read it back.
}

Hint

After write and close, open the file again and use input_int().

void small_main()
{
    File file;

    file.open("highscore.txt", FileMode::Write);
    file.print(950);
    file.close();

    file.open("highscore.txt");
    int score = file.input_int();
    file.close();

    print("High score: ", score);
}