C

C Programming

Master the fundamentals of C programming with comprehensive tutorials, examples, and hands-on exercises

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C Programming Tutorial
Getting Started
Fundamentals
Control Flow
Functions
Arrays & Strings
Pointers
Advanced Topics

Input and Output in C

Input and output operations are essential for interactive programs. C provides several functions for reading input from users and displaying output.

Output Functions

printf() Function

Used to display formatted output to the screen.

printf() Examples 
#include <stdio.h>

int main() {
    int age = 25;
    float height = 5.9;
    char grade = 'A';
    
    printf("Hello, World!\n");
    printf("Age: %d\n", age);
    printf("Height: %.1f feet\n", height);
    printf("Grade: %c\n", grade);
    printf("Multiple values: %d, %.2f, %c\n", age, height, grade);
    
    return 0;
}

Input Functions

scanf() Function

Used to read formatted input from the user.

scanf() Examples 
#include <stdio.h>

int main() {
    int age;
    float salary;
    char grade;
    
    printf("Enter your age: ");
    scanf("%d", &age);
    
    printf("Enter your salary: ");
    scanf("%f", &salary);
    
    printf("Enter your grade: ");
    scanf(" %c", &grade);  // Note the space before %c
    
    printf("\nYou entered:\n");
    printf("Age: %d\n", age);
    printf("Salary: %.2f\n", salary);
    printf("Grade: %c\n", grade);
    
    return 0;
}

Format Specifiers

Specifier Data Type Example
%dintprintf("%d", 42);
%ffloatprintf("%.2f", 3.14);
%ccharprintf("%c", 'A');
%sstringprintf("%s", "Hello");
%lfdoublescanf("%lf", &num);
Important

Always use the address operator (&) with scanf() for variables, except for strings.

Explanation

  • printf: Prints formatted output using format specifiers like %d, %f, %s.
  • scanf: Reads user input; pass variable addresses (e.g., &age) except for strings, which are arrays.
  • Format specifiers: Must match the variable type to avoid undefined behavior or crashes.
  • Whitespace: When reading char, use a leading space in " %c" to eat leftover newlines.
Keywords
C input output, printf, scanf, format specifiers, address-of
Quick Tips
  • Validate scanf return value to ensure inputs were read successfully.
  • Use fgets for safer string input and parse with sscanf.
  • Prefer explicit widths (e.g., %.2f) to format numeric output neatly.
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Next: if...else Statement

Frequently Asked Questions

C is a powerful, general-purpose programming language that's been around since the 1970s. It's the foundation for many modern languages and is essential for system programming, embedded systems, and understanding how computers work at a low level. Learning C gives you a solid foundation in programming fundamentals.

No prior programming experience is required! Our C programming tutorial is designed for complete beginners. We start with the basics and gradually progress to more advanced topics. However, having some basic computer literacy and logical thinking skills will be helpful.

You need a C compiler to run C programs. For beginners, we recommend using our online C compiler which requires no installation. For local development, you can use GCC (GNU Compiler Collection) which is available on Windows (via MinGW), macOS (via Xcode), and Linux. IDEs like Code::Blocks, Dev-C++, or Visual Studio Code are also helpful.

The time to learn C depends on your dedication and prior experience. With consistent practice (1-2 hours daily), you can grasp the basics in 2-4 weeks and become proficient in 2-3 months. Mastering advanced concepts like pointers, memory management, and data structures may take 6-12 months of regular practice.

C programming skills open doors to various career paths including system programming, embedded systems development, operating system development, device driver programming, game development, and firmware development. Many companies in automotive, aerospace, telecommunications, and IoT sectors actively seek C programmers.

Absolutely! C remains highly relevant and is consistently ranked among the top programming languages. It's essential for system programming, embedded systems, IoT devices, and performance-critical applications. Many modern languages are built on C, and understanding C helps you become a better programmer overall.