CBeginner

C Basics

Learn C fundamentals: printf output, variables, data types, arithmetic operators, and constants for absolute beginners.

01Hello, World

main.c

#include <stdio.h>

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

Output

Hello, World!

02Variables and types

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main.c

#include <stdio.h>

int main() {
    int age = 36;
    double height = 1.68;
    char grade = 'A';
    printf("%d %.2f %c\n", age, height, grade);
    return 0;
}

Output

36 1.68 A

03Arithmetic operators

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main.c

#include <stdio.h>

int main() {
    int a = 10, b = 3;
    printf("%d\n", a + b);
    printf("%d\n", a - b);
    printf("%d\n", a * b);
    printf("%d\n", a / b);
    printf("%d\n", a % b);
    return 0;
}

Output

04Constants with #define

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main.c

#include <stdio.h>
#define PI 3.14159

int main() {
    double r = 2.0;
    printf("Area = %.2f\n", PI * r * r);
    return 0;
}

Output

Area = 12.57