Learn C

C Topics

Click on a topic to expand and learn in detail.

• 1. Introduction to C

#include <stdio.h>

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

• 2. Variables & Data Types

int age = 25;
float pi = 3.14;
char grade = 'A';
double salary = 45000.50;
      

• 3. Operators

// Arithmetic: +, -, *, /, %
int sum = 5 + 3;

// Comparison: ==, !=, >, <
int flag = (5 > 3); // 1 = true

// Logical: &&, ||, !
int logic = 1 && 0; // 0 = false
      

• 4. Conditions

int age = 18;

if(age >= 18){
    printf("Adult");
}else{
    printf("Minor");
}

switch(age){
    case 18:
        printf("Exactly 18");
        break;
    default:
        printf("Other age");
}
      

• 5. Loops

// for loop
for(int i=0;i<5;i++){
    printf("%d\n", i);
}

// while loop
int i=0;
while(i<5){
    printf("%d\n", i);
    i++;
}

// do-while loop
int j=0;
do{
    printf("%d\n", j);
    j++;
}while(j<5);
      

• 6. Functions

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

int main(){
    printf("%d", add(5,3));
    return 0;
}
      

• 7. Arrays & Strings

int numbers[5] = {1,2,3,4,5};
printf("%d", numbers[0]); // 1

char name[] = "Alice";
printf("%s", name);
      

• 8. Pointers

int x = 10;
int *ptr = &x;
printf("%d", *ptr); // 10
      

• 9. Advanced C Topics
• Structures
• Dynamic Memory (malloc, free)
• File I/O (fopen, fread, fwrite)
• Preprocessor Directives
• Recursion