Simple c Program

User defined Functions

Function Declarations

 Prototype to perform this task, a user-defined function add Numbers () is defined.

#include <stdio.h>

int addNumbers(int a, int b);         // function prototype

int main()

{

    int n1,n2,sum;

    printf("Enters two numbers: ");

    scanf("%d %d",&n1,&n2);

    sum = addNumbers(n1, n2);        // function call

    printf("sum = %d",sum);

    return 0;

}

int addNumbers(int a,int b)         // function definition  

{

    int result;

    result = a+b;

    return result;                  // return statement

}

A function Declarations is simply the declaration of a function that specifies function's name, parameters and return type. It doesn't contain function body.

A function Declarations gives information to the compiler that the function may later be used in the program.

Syntax of function Declarations

Declarations In the above example, 

int addNumbers(int a, int b);

 is the function Declarations which provides following information to the compiler:

1.   name of the function is addNumbers()

2.   return type of the function is int

3.   two arguments of type int are passed to the function

The function Declarations is not needed if the user-defined function is defined before the main() function.

Calling a function

Control of the program is transferred to the user-defined function by calling it.

Syntax of function call

functionName(argument1, argument2, ...);

In the above example, function call is made using addNumbers(n1,n2); statement inside the main().

 

Function definition

Function definition contains the block of code to perform a specific task i.e. in this case, adding two numbers and returning it.

Syntax of function definition

returnType functionName(type1 argument1, type2 argument2, ...)

{

    //body of the function

}

When a function is called, the control of the program is transferred to the function definition. And, the compiler starts executing the codes inside the body of a function.

Passing arguments to a function

In programming, argument refers to the variable passed to the function. In the above example, two variables n1 and n2 are passed during function call.

The parameters a and b accepts the passed arguments in the function definition. These arguments are called formal parameters of the function.

Functions

Function Definition: Function is a group of statements which performs a specific task. It is also known as Sub-routine or Procedure or Method.

return_type functions name(arguments list)

{

        body of the functions

}

Here are all the parts of a function −

• Return Type − A function may return a value. The return_type is the data type of the value the function returns. Some functions perform the desired operations without returning a value. In this case, the return_type is the keyword void.

• Function Name − This is the actual name of the function. The function name and the parameter list together constitute the function signature.

• Parameters − A parameter is like a placeholder. When a function is invoked, you pass a value to the parameter. This value is referred to as actual parameter or argument. The parameter list refers to the type, order, and number of the parameters of a function. Parameters are optional; that is, a function may contain no parameters.

• Function Body − The function body contains a collection of statements that define what the function does.

·      There are two kinds of c functions:

1.   Library Functions (also known as System defined function)

2. Userdefined functions (written by programmers)

1.   Library Functions are used to perform standard operations eg: squreroot of a number sqrt(x), absolute value fabs(x),scanf(),printf(),and so on.These functions are available alog with the compiler and are used along with the required header files such as math.h, stdio.h, string.h, and so on at the beginning of the programe.

2.   User defined functions are self-contained blocks of statement which are written by the user to compute a value or to perform a task.They can be called by the main() function repeatedly as per the requirement.  

List of C Programs

-c program to sort an array using function

-Even And Odd Numbers

-c program the division operation

-Sum of Series 1+2+3+..+n

-C in size operator

-c program for pre decrement and post decrement

-c program to implement simple if-else in c

-Simple if statement

-Calculate Simple interest

-Swap the values of two Variables using three variables

-Two Variable of sum

-Palindrome number using for loop

-Fibonacci Series using while loop

Even And Odd Numbers

• Two methods available in c programing...

#include <stdio.h>
int main()
{
    int i;

    printf("Enter an integer: ");
    scanf("%d", &i);

    if(i % 2 == 0)
        printf("%d is even.", i);
    else
        printf("%d is odd.", i);

    return 0;
};

Output :

(2) Methods Condition Operator

Program :

#include <stdio.h>
int main()
{
    int A;

    printf("Enter an integer: ");
    scanf("%d", &A);

    (A % 2 == 0) ? printf("%d is even.", A) : printf("%d is odd.", A);

    return 0;
}

Output :

c program to sort an array using function

Program :

#include<stdio.h>
#include<conio.h>
#define MAX 100     // maximum no of elements of array
int sortArray(int);
int array[MAX];
int main()
{
  int i,size;
  printf("\n>>>> PROGRAM TO SORT ARRAY USING FUNCTION <<<<\n\n");
  printf("\n Enter the size of array: ");
  scanf("%d",&size);
  printf("\n Enter the %d elements of array: \n",size);
  for(i=0;i<size;i++)
  {
   printf("\n array[%d]=",i);
   scanf("%d", &array[i]);
  }
  sortArray(size);    //calling sortArray() function
   printf("\n The Sorted elements of array are:");
   for(i=0;i<size;i++)
   {
     printf(" %d",array[i]);
   }
   getch();
   return 0;
}

sortArray(n)   // function for sorting array elements
{
  int temp=0,i,j;   // temp var is temporary variable used for swapping
  for(i=0;i<n;i++)
  {
    for(j=i+1;j<n;j++)
    {
      if(array[i]>array[j])
      {
        temp=array[i];   //swapping for the array to be sorted
        array[i]= array[j];
        array[j]=temp;
      }
    }
  }

}

Output :