Variable Arguments in C-Language

 

Variable Arguments in  C-Language

Variable Arguments

• Variable length argument is a feature that allows a function to receive any number of arguments.
• There are situations where we want a function to handle variable number of arguments according to requirement.

1.  Sum of given numbers.
2.  Minimum of given numbers. and many more.

Variable number of arguments are represented by three dotes (…)
Syntax:

    datatype functionname(datatype,...)
    {
    ...
    ...
    }
    
    void main()
    {
    functionname(v1,v2,v3);
    functionname(v1,v2,v3,v4,v5);
    }

/* C Variable Length Arguments - This program
 * demonstrates variable length arguments in C
 */

#include<stdio.h>
#include<stdarg.h>
#include<conio.h>

int avg(int num, ...)
{
	va_list valist;
	int sum = 0;
	int i;

	// initializing valist for num number of arguments
	va_start(valist, num);

	// now accessing all the arguments that is assigned to valist
	for(i=0; i<num; i++)
	{
		sum = sum + va_arg(valist, int);
	}

	// now cleaning the memory reserved for the valist
	va_end(valist);

	return sum/num;
}

void main()
{
	int num1=10, num2=20, num3=30;
	clrscr();

	printf("The average is %d", avg(3, num1, num2, num3));

	getch();
}

Output:
The average is 20

Files In C Language

 

Files In C Language

File : File is a collection of data or information which is used to store the data permanently
Types of files:
1.Text Files
2.Document Files
3.Audio Files
4.Video Files
5.PDF Files ...


File Operations
1.Open or create a file
2.Write the data into the file
3.Read the data from the file
4.close a file
Open file

FILE *fopen( const char * filename, const char * mode );

Here, filename is a string literal, which you will use to name your file, and access mode can have one of the following values −

Sno	Mode	Description
1	r	Opens an existing text file for reading purpose.
2	w	Opens a text file for writing. If it does not exist, then a new file is created. Here your program will start writing content from the beginning of the file.
3	a	Opens a text file for writing in appending mode. If it does not exist, then a new file is created. Here your program will start appending content in the existing file content.
4	r+	Opens a text file for both reading and writing.
5	w+	Opens a text file for both reading and writing. It first truncates the file to zero length if it exists, otherwise creates a file if it does not exist.
6	a+	Opens a text file for both reading and writing. It creates the file if it does not exist. The reading will start from the beginning but writing can only be appended.

If you are going to handle binary files, then you will use following access modes instead of the above mentioned ones −

  "rb", "wb", "ab", "rb+", "r+b", "wb+", "w+b", "ab+", "a+b"

Closing File:

int fclose( FILE *fp );
Close a file using fclose( ) function

Writing a File:

fprintf(file,"Data")

fputs("Data",File)

Program:

#include <stdio.h>
#include <conio.h>
void main() {
   FILE *fp;
   fp = fopen("test.txt", "w+");
   fprintf(fp, "This is testing File\n");
   fputs("This is testing File\n", fp);
   fclose(fp);
   printf("Success");
   getch();
}

Reading a File

fscanf(File,"type of data",variable);

fgets(variable,size, FILE)

Program

#include <stdio.h>
#include <conio.h>

void main() {

   FILE *fp;
   char x[255];

   fp = fopen("test.txt", "r");
   fscanf(fp, "%s", x);
   printf("1 : %s\n", x );

   fgets(x, 255, (FILE*)fp);
   printf("2: %s\n", x );
   
   fclose(fp);
   printf("Success");
   getch();

}

Functions in C Language

 

C Functions

Function is a collection of statements used to perform specific operation.In C Language these function are classified into following types

1. predefined Function
2. UserDefined Function

PreDefined Functions

If any function already designed by the C Develophers is known as predefined functions .These are classified into following types
1. printf()
2. Scanf()
3. getch()
4. clrscr()
5. sizeof() ...ete

UserDefined Function

If any function designed by the programmer is known as user defined function
Syntax

  returntype functionname(list of paramers/no parameters);    //function Declaration
  returntype functionname(list of paramers/no parameters)      //function Body
  {
  ....
  ....
  ....
  ....
  }
  

in the above syntax first you declare the function.Ofter you declare the function body
These functions are classified into fallowing types

1. Parametarized Function
2. NoParametarized Function

Parametarized Function:

If any function signature contains list of parameters is known as Parametarized Function.
Syntax

  returntype functionname(datatype variable1,datatype variable2,....);    //function Declaration
  returntype functionname(datatype variable1,datatype variable2,....)      //function Body
  {
  ....
  ....
  ....
  ....
  }
  

NoParametarized Function:

If any function signature does not contains list of parameters is known as NoParametarized Function.
Syntax

  returntype functionname();    //function Declaration
  returntype functionname()     //function Body
  {
  ....
  ....
  ....
  ....
  }
  

Based on the return type these functions are classified into following types

1. No Returntype With NoParametarized Function
2. No Returntype With Parametarized Function
3. Returntype With NoParametarized Function
4. Returntype With Parametarized Function

No Returntype With NoParametarized Function

#include<stdio.h>
#include<conio.h>
void max();
void max()
{
int x,y;
printf("Enter x,y values");
scanf("%d%d",&x,&y);
if(x>y)
{
printf("x is max");
}
else
{
prinf("y is max");
}
};
void main()
{
clrscr();
max();
getch();
}
 

No Returntype With Parametarized Function

#include<stdio.h>
#include<conio.h>
void max(int x,int y);
void max(int x,int y)
{

if(x>y)
{
printf("x is max");
}
else
{
prinf("y is max");
}
};
void main()
{
clrscr();
int x,y;
printf("Enter x,y values");
scanf("%d%d",&x,&y);
max(x,y);
getch();
}
 

Returntype With NoParametarized Function

#include<stdio.h>
#include<conio.h>
int max();
int max()
{
int x,y;
printf("Enter x,y values");
scanf("%d%d",&x,&y);
if(x>y)
{
return x;
}
else
{
return y;
}
};
void main()
{
clrscr();
printf("%d",max());
getch();
}
 

Returntype With Parametarized Function

#include<stdio.h>
#include<conio.h>
int  max(int x,int y);
int  max(int x,int y)
{

if(x>y)
{
return x;
}
else
{
return y;
}
};
void main()
{
clrscr();
int x,y;
printf("Enter x,y values");
scanf("%d%d",&x,&y);
printf("%d",max(x,y));
getch();
}
 

Function Calling

Function Calling Syntax :
functionname(arguments,...);
Example: max(10,20)
Here Max is a functionname
10,20 are the arguments

C - Recursion

The C programming language supports recursion, i.e., a function to call itself. But while using recursion, programmers need to be careful to define an exit condition from the function, otherwise it will go into an infinite loop.
Syntax :

 void recursion() {
   recursion(); /* function calls itself */
}

int main() {
   recursion();
}
 

#include<stdio.h>
#include<conio.h>
int factorial(int i) {

   if(i <= 1) {
      return 1;
   }
   return i * factorial(i - 1);
}

void  main() {
   int i = 5;
   printf("Factorial of %d is %d//n", i, factorial(i));
   getch();
}

Memory Management in C-Language

 

  Memory Management  

Dynamic Memory Allocation in C

• The process of allocating memory at runtime is known as dynamic memory allocation.
• Library routines known as memory management functions are used for allocating and freeing memory during execution of a program.
• These functions are defined in stdlib.h header file.

Function	Description
malloc()	allocates requested size of bytes and returns a void pointer pointing to the first byte of the allocated space
calloc()	allocates space for an array of elements, initialize them to zero and then returns a void pointer to the memory
Free	releases previously allocated memory
realloc	modify the size of previously allocated space

Memory Allocation Process

• Global variables, static variables and program instructions get their memory in permanent storage area whereas local variables are stored in a memory area called Stack.
• The memory space between these two region is known as Heap area. This region is used for dynamic memory allocation during execution of the program. The size of heap keep changing.

Allocating block of Memory

• malloc() function is used for allocating block of memory at runtime.
• This function reserves a block of memory of the given size and returns a pointer of type void.
• This means that we can assign it to any type of pointer using typecasting.
• If it fails to allocate enough space as specified, it returns a NULL pointer.

Syntax:

    void* malloc(byte-size)

calloc()

• It is another memory allocation function that is used for allocating memory at runtime.
• calloc function is normally used for allocating memory to derived data types such as arrays and structures.
• If it fails to allocate enough space as specified, it returns a NULL pointer.

Syntax:

void *calloc(number of items, element-size)

realloc()

• realloc() changes memory size that is already allocated dynamically to a variable.

Syntax:

    void* realloc(pointer, new-size)

String Palindrome Program in Python

                  

    String  Palindrome Program in Python

Examples: 
Input : malayalam
Output : Yes

Input : MSK
Output : No

Program:

def checkPalindrome(str):

    return str == str[::-1]

 

 

# Driver code

s = "malayalam"

ans = checkPalindrome(s)

 

if ans:

    print("Palindrome")

else:

    print("Not Palindrome")

OutPut:

Palindrome

Area Of Equilateral Triangle In Python

                 

    Area Of Equilateral Triangle In Python

This is how an equilateral triangle looks like:
As you can see, this is an equilateral triangle with a side length of “a” units and a height of “h” units.
The altitude of an equilateral triangle cuts the opposite side at right angles. So, by using the Pythagoras theorem, we can calculate the height of an equilateral triangle to be sqrt(3/4)a.
Thus, the area of an equilateral triangle = 1/2 * sqrt (3/4)a * a
Area = (sqrt 3)/4 * a^2

Program:

import math

a=float(input("enter side of the triangle: "));

area=(math.sqrt(3)/4)*a*a;

print("Area Of Equilateral Triangle ",area);

OutPut:

enter side of the triangle: 10

Area Of Equilateral Triangle  43.301270189221924

Simple Calculator Program In Python

                

    Simple Calculator Program In Python

Program:

# define functions  

def add(x, y):  

   

   return x + y 

def sub(x, y): 

   

   return x - y 

def mul(x, y): 

   

   return x * y 

def div(x, y): 

   

   return x / y  

# take input from the user  

print("Select operation.")  

print("1.Addition")  

print("2.Subtraction")  

print("3.Multiplication")  

print("4.Division")  

  

choice = input("Enter choice(1/2/3/4):")  

  

num1 = int(input("Enter first number: "))  

num2 = int(input("Enter second number: "))  

  

if choice == '1':  

   print(num1,"+",num2,"=", add(num1,num2))  

  

elif choice == '2':  

   print(num1,"-",num2,"=", sub(num1,num2))  

  

elif choice == '3':  

   print(num1,"*",num2,"=", mul(num1,num2))  

elif choice == '4':  

   print(num1,"/",num2,"=", div(num1,num2))  

else:  

   print("Invalid input")  

OutPut:

Select operation.

1.Addition

2.Subtraction

3.Multiplication

4.Division

Enter choice(1/2/3/4):2

Enter first number: 12

Enter second number: 23

12 - 23 = -11

Check whether a number can be expressed as a sum of two prime numbers In Python

               

    Check whether a number can be expressed as a sum of two prime numbers In Python

For example, the number 34 is given as input.

34 = 3 + 31
34 = 5 + 29
34 = 11 + 23
34 = 17 + 17

Program:

# Python program to check whether a number can be expressed as a sum of two prime numbers

def prime(n):

    isPrime = 1

    for i in range (2,int(n/2),1):

        if(n % i == 0):

            isPrime = 0

            break

    return isPrime

n = int(input("Enter a number : "))

f = 0;

i = 2

for i in range (2,int(n/2),1):

    if(prime(i) == 1):

        if(prime(n-i) == 1):

            print(n,"can be expressed as the sum of",i,"and",n-i)

            f = 1;

if (f == 0):

    print(n,"cannot be expressed as the sum of two prime numbers")

OutPut:

Enter a number : 34

34 can be expressed as the sum of 3 and 31

34 can be expressed as the sum of 5 and 29

34 can be expressed as the sum of 11 and 23

Enter a number : 35

35 can be expressed as the sum of 4 and 31

Enter a number : 37

37 cannot be expressed as the sum of two prime numbers

replace all 0's with 1 in a given integer In Python

              

        Replace all 0's with 1 in a given integer In Python

Input: 102405
Output: 112415

Program:

# Python program to replace all 0’s with 1 in a given integer

def re(n):

    if (n == 0):

        return 0;

# Extract the last digit and change it if needed

    digit = n % 10

    if (digit == 0):

        digit = 1

    return re(int(n/10)) * 10 + digit

n = int(input("Enter the number : "))

print("Number after replacement : ",re(n))

OutPut:

Enter the number : 123034

Number after replacement :  123134

Python program to print the Armstrong numbers between the two intervals

             

        Python program to print the Armstrong numbers between the two intervals

An Armstrong number of three digits is an integer such that the sum of the cubes of its digits is equal to the number itself. For example, 153  is an Armstrong

Program:

# Python program to print the Armstrong numbers between the two intervals

import math

n1 = int(input("Enter start value : "))

n2 = int(input("Enter end value : "))

result = 0

n = 0

for i in range(n1+1 ,n2,1):

    t2 = i

    t1 = i

    while (t1 != 0):

        t1 = int(t1/10)

        n = n + 1

    while (t2 != 0):

        remainder = t2 % 10

        result = result + math.pow(remainder, n)

        t2 = int(t2/10)

    if (result == i):

        print(i)

    n = 0

    result = 0

OutPut:

Enter start value : 100

Enter end value : 500

153

370

371

407

Enter start value : 200

Enter end value : 1000

370

371

407

Prime Number Program in Given Range in Python

  

         Prime Number Program in Given Range in Python

Prime number in C: Prime number is a number that is greater than 1 and divided by 1 or itself. In other words, prime numbers can't be divided by other numbers than itself or 1. For example 2, 3, 5, 7, 11, 13, 17, 19, 23.... are the prime numbers.

factors Program In Python

            

        Factors Program In Python

the factors of number 10 are
1 * 10 = 10
2 * 5 = 10
5* 2 = 10
10* 1 = 10

Program:

n = int(input("Enter a number : "))

count = 0

for i in range(1, n+1, 1):

    if(n % i == 0):

        count = count + 1

        print(i, end = " ")

print("\nTotal factors of",n," is :",count)

OutPut:

Enter a number : 10

1 2 5 10 

Total factors of 10 : 4

Enter a number : 20

1 2 4 5 10 20 

Total factors of 20  is : 6

Abundant number In Python

           

        Abundant number In Python

An abundant number is a number for which the sum of its proper divisors is greater than the
 number itself.
The divisors of 12 are 1, 2, 3, 4 and 6.
The sum of divisors of 12 is 16.
12 < 16.Hence, 12 is an abundant number.

Program:

n = int(input("Enter N Value"))

sum = 0

for i in range(1,n):

if(n % i == 0):

sum = sum + i

if(n < sum):

print("It is a Abundant Number")

else:

print("Not Abundant Number")

OutPut:

Enter N Value12

It is a Abundant Number

Enter N Value4

Not Abundant Number