C Tutorial

C Tutorial C Language Environment Setup Execution flow of C program C printf and Scanf C Data type C Token Variable in C Operators in C Comments in C Escape Sequence in C C – Storage Classes C Decision control statement Loop Statement in C Break, continue and goto statement in C Type Casting in C Function in C Recursion in C String in C C Array Pointer in C Dynamic memory allocation C –Structure Nested Structure in C Union in C File Handling in C C pre-processor Static Function In C Sizeof In C Selection Sort In C Scope Of Variables In C Runtime Vs Compile Time In C Random Access Lseek In C Queue Implementation In C Pseudo Code In C Prototype In C Pointer To Pointer In C Pointer Arithmetic In C Passing Array To Function In C Null Character In C Merge Sort In C Macros In C Library Functions In C Memory Leak In C Int In C Goto And Labels In C Fibonacci Series In C Fflush In C Derived Data Types In C Data Types In C Const Vs Volatile In C Character Set In C Character Class Tests In C Calloc In C C Pointers Arrays In C Include In C Clrscr In C C Vs Java String Literals In C Types Of Pointers In C Variables In C Volatile In C Why C Is A Middle Level Language Infix To Postfix Program In C Ceil function in C LCM of two numbers in C Quick sort in C Static in C function pointer as argument in C Top Array Keywords in C Add two numbers using the function in C Armstrong program in C using function Array, Declaring Arrays and Array Initialization Limitations of Inline Function in C Merge and Merge sort with example in C Do-While Loop in C For Loop in C While-Loop in C Difference between while and do-while loop in C Array Of Structures in C Data Structures And Algorithms in C Types Of Structures In C How to Avoid Structure Padding in C Use of Structure in C Do WHILE LOOP in C Programming Examples For Loop in C Programming Examples Entry Control Loop in C Exit control loop in C Infinite loop in C Nested loop in C pow() function in C String Handling functions in C Prime Number code in C Factorial Program in C using For Loop Factorial Program in C Using While Loop Fibonacci Series in C Using For Loop Fibonacci series in C using while loop Prime Number Program in C using for Loop While Loop in C programming examples Built-in functions in C Assert() Function C vs Java Strings Call Back Function in Embedded C Else If Ladder fgets() function Ftell() Function getc() function getch() function gets() function Heap Sort Nested if-else statement Pi() Function Positioning of file Write() function abs() function in C Attributes in C C program to find factorial of a number using Recursion Ferror() in c fopen() function in C Fibonacci series program in C using Recursion Formatted Input and output function in C Snake Game in C User Defined Functions in C Beep() function in C Cbrt() function in C Hook() function in C Isalnum() function in C C Program to find the Roots of a Quadratic Equation C Switch Statements Difference between rand() and srand() function in C Difference between while and for loop in C Doubly Linked list in C Example of Iteration in C How to use atoi() function in C How to use floor() function in C How to use sine() function in C How to use Typedef Struct in C Integer Promotions in C C Program to Find Largest Number Using Dynamic Memory Allocation C Program to Find the Largest Number using Ternary Operator C/C++ Program to Find the Size of int, float, double and char Find the Largest Three Distinct Elements in an Array using C/C++ Loop Questions in C Modulus on Negative Numbers in C Multiplication table program in C using For loop Nested Loops in C Programming Examples C Program for Mean and Median of an Unsorted Array Results of Comparison Operations in C and C++ Reverse a Stack using Recursion in C Simple hash() function in C strcat() Function in C Sum of N numbers in C using For loop Use of free() function in C Write a program that produces different results in C and C++

Function in C

Function is a group of statements that are used to perform any task. In other words, we can say that a function is a self- contained a block of programs that perform a coherent task. Why to use function A function is used to divide a large code into modules that help us to debug and maintain the code. We can call any function multiple times. There are various advantages of function:

  • Code re-usability
  • Easy to debug the program
  • Code optimization.
Types of Functions In C language, there are two types of functions that are given below:  

  1. Library Function :
A library function is used to declare the c header file such as scanf(), printf() and many more.
  1. User-defined function
User define function is used to create own function and we can use it multiple times. Defining a Function We can define a function by using the following syntax: Syntax:
return typefunction name( parameter list ) {
body of the function
}
The function definition consists of a function header and a function body. There are the following parts of a function.
  1. Return type: A function may return a value. If we don’t want to return a value then we have to use void.
  2. Function name: We can define the function name.
  3. Parameters: We can pass the value in function at the time of calling.
  4. Function body: Function body is the collection of statements.
Let us consider an example:
#include <stdio.h>
void sum(); // declaring a function
int a=5,b=10, c;
void sum() // defining function
 {
 c=a*b;
 printf("Multiplication of (A*B) : %d\n", c);
 }
int main()
 {
 sum(); // calling function
 return 0;
 }
Output
Multiplication of (A*B) : 50
Call by value and call by Reference in C In C language, there are two ways to pass the value of data to function.
  • call by value.
  • call by reference.
 

Call by value: We can’t change the original value at the time of passing value in the function but it can be changed for the current function only. It will not change the value of a variable inside the caller method such as main().

Let us consider an example:
#include<stdio.h>
void abc(int id, int mob)
 {
 printf(" Passing value inside the abc function");
  }
int main()
{
int id=101, mob=90972762;
abc(id, mob); // passing value to the function
printf("\nValue of ID: %d",id);
printf("\nValue of NAME: %d",mob);
return 0;
}
Output
Passing value inside the abc function
Value of ID: 101
Value of NAME: 90972762
Call by reference: We can change the original value while using call by reference through pass the reference (address).

Let us consider an example:
#include <stdio.h>
void fun(int *n) {
 printf("Adding value before inside the function=%d \n",*n);
 (*n) += 10;
 printf("Adding value after inside the function=%d \n", *n);
}
int main() {
 int x=10;
 printf("Before function call x=%d \n", x);
 fun(&x);//passing reference in function
 printf("After function call x=%d \n", x);
 return 0;
 }
Output
Before function call x=10 
Adding value before inside the function=10 
Adding value after inside the function=20 
After function call x=20



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