Skip to content
My Compiler
LoginRegister

Learn C: a Beginner Tutorial

Follow these lessons in order. Each one has a short explanation and code you can run instantly in My Compiler.

  1. Lesson 1: Hello, World!

    Every language starts here: print a message to the screen to check that everything works.

    #include <stdio.h>

int main(void) {
    printf("Hello, World!\n");
    return 0;
}
    Open in compiler

  2. Lesson 2: Variables

    Variables store values such as text, whole numbers and decimals so you can reuse them.

    #include <stdio.h>

int main(void) {
    char name[] = "Ada";
    int age = 21;
    double height = 1.75;
    printf("%s %d %.2f\n", name, age, height);
    return 0;
}
    Open in compiler

  3. Lesson 3: Conditions

    if / else lets your program choose a path depending on a value.

    #include <stdio.h>

int main(void) {
    int age = 18;
    if (age >= 18) {
        printf("Adult\n");
    } else if (age >= 13) {
        printf("Teenager\n");
    } else {
        printf("Child\n");
    }
    return 0;
}
    Open in compiler

  4. Lesson 4: Loops

    Loops repeat a block of code: use for when you know the count and while when you wait for a condition.

    #include <stdio.h>

int main(void) {
    for (int i = 1; i <= 5; i++) {
        printf("%d\n", i);
    }
    int n = 3;
    while (n > 0) {
        printf("Countdown %d\n", n--);
    }
    return 0;
}
    Open in compiler

  5. Lesson 5: Functions

    A function packs code into a reusable block that takes inputs and returns a result.

    #include <stdio.h>

int add(int a, int b) {
    return a + b;
}

int main(void) {
    printf("%d\n", add(2, 3));
    return 0;
}
    Open in compiler

  6. Lesson 6: Fibonacci sequence

    Each number is the sum of the two before it. A classic exercise that combines variables, loops and arithmetic.

    #include <stdio.h>

int main(void) {
    int a = 0, b = 1;
    for (int i = 0; i < 10; i++) {
        printf("%d ", a);
        int next = a + b;
        a = b;
        b = next;
    }
    return 0;
}
    Open in compiler