Comprehensive C Language Cheatsheet for Programmers

This cheatsheet serves as a concise reference for the key concepts of the C programming language, derived from the Tutorialspoint C Language Cheatsheet.

1. Basic Structure of a C Program

• Every C program consists of functions, with main() being the entry point.
• Syntax:

#include <stdio.h>

int main() {
    // code goes here
    return 0;
}

2. Data Types

C has several built-in data types:

• int: Integer type
• float: Floating-point type
• double: Double-precision floating-point type
• char: Character type

Example:

int age = 25;
float weight = 70.5;
char grade = 'A';

3. Variables

• Variables must be declared before use.
• Syntax for declaration:

data_type variable_name;

Example:

int count;
float temperature;

4. Control Structures

a. Conditional Statements

• if statement:

if (condition) {
    // code to execute if condition is true
}

b. Loops

• for loop:

for (initialization; condition; increment) {
    // code to execute
}

Example:

for (int i = 0; i < 5; i++) {
    printf("%d\n", i); // prints numbers 0 to 4
}

5. Functions

• Functions are blocks of code designed to perform a particular task.
• Syntax:

return_type function_name(parameters) {
    // code
    return value; // optional
}

Example:

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

6. Arrays

• An array is a collection of variables of the same type.
• Declaration:

data_type array_name[size];

Example:

int numbers[5]; // array of 5 integers

7. Pointers

• Pointers hold the memory address of another variable.
• Declaration:

data_type *pointer_name;

Example:

int a = 10;
int *p = &a; // p points to the address of a

8. Input and Output

• Use printf() for output and scanf() for input.

Example:

int num;
printf("Enter a number: ");
scanf("%d", &num);

9. Comments

• Comments are used to explain code and are ignored by the compiler.
• Single-line comment: // comment
• Multi-line comment: /* comment */

Conclusion

This cheatsheet covers the essentials of C programming, including the structure of a program, data types, control structures, functions, arrays, pointers, and basic input/output operations. Understanding these concepts is crucial for beginners to start coding in C effectively.