C programm : Decimal to binary conversion

C program to convert decimal to binary: c language code to convert an integer from decimal number system(base-10) to binary number system(base-2). Size of integer is assumed to be 32 bits. We use bitwise operators to perform the desired task. We right shift the original number by 31, 30, 29, ..., 1, 0 bits using a loop and bitwise AND the number obtained with 1(one), if the result is 1 then that bit is 1 otherwise it is 0(zero). 

#include <stdio.h>
 
int main()
{
  int n, c, k;
 
  printf("Enter an integer in decimal number system\n");
  scanf("%d", &n);
 
  printf("%d in binary number system is:\n", n);
 
  for (c = 31; c >= 0; c--)
  {
    k = n >> c;
 
    if (k & 1)
      printf("1");
    else
      printf("0");
  }
 
  printf("\n");
 
  return 0;
}

Above code only prints binary of integer, but we may wish to perform 
operations on binary so in the code below we are storing the binary in a
 string. We create a function which returns a pointer to string which is
 the binary of the number passed as argument to the function.  

C program : to find hcf and lcm using function

#include <stdio.h>
 
long gcd(long, long);
 
int main() {
  long x, y, hcf, lcm;
 
  printf("Enter two integers\n");
  scanf("%ld%ld", &x, &y);
 
  hcf = gcd(x, y);
  lcm = (x*y)/hcf;
 
  printf("Greatest common divisor of %ld and %ld = %ld\n", x, y, hcf);
  printf("Least common multiple of %ld and %ld = %ld\n", x, y, lcm);
 
  return 0;
}
 
long gcd(long x, long y) {
  if (x == 0) {
    return y;
  }
 
  while (y != 0) {
    if (x > y) {
      x = x - y;
    }
    else {
      y = y - x;
    }
  }
 
  return x;
}

C program : to find hcf and lcm using recursion

#include <stdio.h>
 
long gcd(long, long);
 
int main() {
  long x, y, hcf, lcm;
 
  printf("Enter two integers\n");
  scanf("%ld%ld", &x, &y);
 
  hcf = gcd(x, y);
  lcm = (x*y)/hcf;
 
  printf("Greatest common divisor of %ld and %ld = %ld\n", x, y, hcf);
  printf("Least common multiple of %ld and %ld = %ld\n", x, y, lcm);
 
  return 0;
}
 
long gcd(long a, long b) {
  if (b == 0) {
    return a;
  }
  else {
    return gcd(b, a % b);
  }
}

c program to find hcf and lcm

C program to find hcf and lcm: The code below finds highest common factor and least common multiple of two integers. HCF is also known as greatest common divisor(GCD) or greatest common factor(gcf).

#include <stdio.h>
 
int main() {
  int a, b, x, y, t, gcd, lcm;
 
  printf("Enter two integers\n");
  scanf("%d%d", &x, &y);
 
  a = x;
  b = y;
 
  while (b != 0) {
    t = b;
    b = a % b;
    a = t;
  }
 
  gcd = a;
  lcm = (x*y)/gcd;
 
  printf("Greatest common divisor of %d and %d = %d\n", x, y, gcd);
  printf("Least common multiple of %d and %d = %d\n", x, y, lcm);
 
  return 0;
}

C program : Factorial using recursion

#include<stdio.h>
 
long factorial(int);
 
int main()
{
  int num;
  long f;
 
  printf("Enter a number to find factorial\n");
  scanf("%d", &num); 
 
  if (num < 0)
    printf("Negative numbers are not allowed.\n");
  else
  {
    f = factorial(num);
    printf("%d! = %ld\n", num, f);
  }
 
  return 0;
}
 
long factorial(int n)
{
  if (n == 0)
    return 1;
  else
    return(n * factorial(n-1));
}

C program : Factorial using function

#include <stdio.h>
 
long factorial(int);
 
int main()
{
  int number;
  long fact = 1;
 
  printf("Enter a number to calculate it's factorial\n");
  scanf("%d", &number);
 
  printf("%d! = %ld\n", number, factorial(number));
 
  return 0;
}
 
long factorial(int n)
{
  int c;
  long result = 1;
 
  for (c = 1; c <= n; c++)
    result = result * c;
 
  return result;
}

C program : Factorialusing for loop

#include <stdio.h>
 
int main()
{
  int c, n, fact = 1;
 
  printf("Enter a number to calculate it's factorial\n");
  scanf("%d", &n);
 
  for (c = 1; c <= n; c++)
    fact = fact * c;
 
  printf("Factorial of %d = %d\n", n, fact);
 
  return 0;
}

c pro. : Factorial

Factorial program in c: c code to find and print factorial of a number, three methods are given, first one uses a for loop, second uses a function to find factorial and third using recursion. Factorial is represented using !, so five factorial will be written as 5!, n factorial as n!. Also
n! = n*(n-1)*(n-2)*(n-3)...3.2.1 and zero factorial is defined as one i.e. 0!=1.

Add digits using recursion

#include <stdio.h>
 
int add_digits(int);
 
int main() {
  int n, result;
 
  scanf("%d", &n);
 
  result = add_digits(n);
 
  printf("%d\n", result);
 
  return 0;
}
 
int add_digits(int n) {
  static int sum = 0;
 
  if (n == 0) {
    return 0;
  }
 
  sum = n%10 + add_digits(n/10);
 
  return sum;
}

C program : add digits of number in c

C program to add digits of a number: Here we are using modulus operator(%) to extract individual digits of number and adding them. 

#include <stdio.h>
 
main()
{
   int n, sum = 0, remainder;
 
   printf("Enter an integer\n");
   scanf("%d",&n);
 
   while(n != 0)
   {
      remainder = n % 10;
      sum = sum + remainder;
      n = n / 10;
   }
 
   printf("Sum of digits of entered number = %d\n",sum);
 
   return 0;
}

c program : to check leap year

c program to check leap year: c code to check leap year, year will be entered by the user. Please read the leap year article before reading the code, it will help you to understand the program.

#include <stdio.h>
 
int main()
{
  int year;
 
  printf("Enter a year to check if it is a leap year\n");
  scanf("%d", &year);
 
  if ( year%400 == 0)
    printf("%d is a leap year.\n", year);
  else if ( year%100 == 0)
    printf("%d is not a leap year.\n", year);
  else if ( year%4 == 0 )
    printf("%d is a leap year.\n", year);
  else
    printf("%d is not a leap year.\n", year);  
 
  return 0;
}

C programming : Check vowel using switch statement

c program : to check whether input alphabet is a vowel or not

This code checks whether an input alphabet is a vowel or not. Both lower-case and upper-case are checked.

#include <stdio.h>
 
main()
{
  char ch;
 
  printf("Enter a character\n");
  scanf("%c", &ch);
 
  if (ch == 'a' || ch == 'A' || ch == 'e' || ch == 'E' || ch == 'i' || ch == 'I' || ch =='o' || ch=='O' || ch == 'u' || ch == 'U')
    printf("%c is a vowel.\n", ch);
  else
    printf("%c is not a vowel.\n", ch);
 
  return 0;
}

Function to check vowel

int check_vowel(char a)
{
    if (a >= 'A' && a <= 'Z')
       a = a + 'a' - 'A';   /* Converting to lower case or use a = a + 32 */
 
    if (a == 'a' || a == 'e' || a == 'i' || a == 'o' || a == 'u')
       return 1;
 
    return 0;
}

C program : to perform addition, subtraction, multiplication and division

C program to perform basic arithmetic operations i.e. addition , subtraction, multiplication and division of two numbers. Numbers are assumed to be integers and will be entered by the user .

Pro. :-

#include <stdio.h>
 
int main()
{
   int first, second, add, subtract, multiply;
   float divide;
 
   printf("Enter two integers\n");
   scanf("%d%d", &first, &second);
 
   add      = first + second;
   subtract = first - second;
   multiply = first * second;
   divide   = first / (float)second;   //typecasting
 
   printf("Sum = %d\n",add);
   printf("Difference = %d\n",subtract);
   printf("Multiplication = %d\n",multiply);
   printf("Division = %.2f\n",divide);
 
   return 0;
}

Find odd or even using conditional operator

#include<stdio.h>
 
main()
{
   int n;
 
   printf("Enter an integer\n");
   scanf("%d",&n);
 
   n%2 == 0 ? printf("Even number\n") : printf("Odd number\n");
 
   return 0;
}

C program : to check odd or even without using bitwise or modulus operator

#include<stdio.h>
 
main()
{
   int n;
 
   printf("Enter an integer\n");
   scanf("%d",&n);
 
   if ( (n/2)*2 == n )
      printf("Even\n");
   else
      printf("Odd\n");
 
   return 0;
}

C program : to check odd or even using bitwise operator

#include<stdio.h>
 
main()
{
   int n;
 
   printf("Enter an integer\n");
   scanf("%d",&n);
 
   if ( n & 1 == 1 )
      printf("Odd\n");
   else
      printf("Even\n");
 
   return 0;
}

C program :to check odd or even using modulus operator

#include<stdio.h>
 
main()
{
   int n;
 
   printf("Enter an integer\n");
   scanf("%d",&n);
 
   if ( n%2 == 0 )
      printf("Even\n");
   else
      printf("Odd\n");
 
   return 0;
}

c program : to check odd or even

 check odd or even :-

c program to check odd or even: We will determine whether a number is odd or even by using different methods all are provided with a code in c language. As you have study in mathematics that in decimal number system even numbers are divisible by 2 while odd are not so we may use modulus operator(%) which returns remainder, For example 4%3 gives 1 ( remainder when four is divided by three). Even numbers are of the form 2*p and odd are of the form (2*p+1) where p is is an integer.
We can use bitwise AND (&) operator to check odd or even, as an example consider binary of 7 (0111) when we perform 7 & 1 the result will be one and you may observe that the least significant bit of every odd number is 1, so ( odd_number & 1 ) will be one always and also ( even_number & 1 ) is zero.
In c programming language when we divide two integers we get an integer result, For example the result of 7/3 will be 2.So we can take advantage of this and may use it to find whether the number is odd or even. Consider an integer n we can first divide by 2 and then multiply it by 2 if the result is the original number then the number is even otherwise the number is odd. For example 11/2 = 5, 5*2 = 10 ( which is not equal to eleven), now consider 12/2 = 6 and 6 *2 = 12 ( same as original number). These are some logic which may help you in finding if a number is odd or not.

c program : comming soon ...

:) coming sooon

c program : to add two numbers

#include<stdio.h>
 
main()
{
   int a, b, c;
 
   printf("Enter two numbers to add\n");
   scanf("%d%d",&a,&b);
 
   c = a + b;
 
   printf("Sum of entered numbers = %d\n",c);
 
   return 0;
}

C PROGRAM : Print integer

#include <stdio.h>
 
int main()
{
  int a;
 
  printf("Enter an integer\n");
  scanf("%d", &a);
 
  printf("Integer that you have entered is %d\n", a);
 
  return 0;
}