#include <stdio.h>
 
int main()
{
   int n, sum = 0, c, array[100];
 
   scanf("%d", &n);
 
   for (c = 0; c < n; c++)
   {
      scanf("%d", &array[c]);
      sum = sum + array[c];
   }
 
   printf("Sum = %d\n",sum);
 
   return 0;
}

/*

Output ::

5 4 3 2 1 

Sum = 15

*/

#include <stdio.h>
 
int main()
{
   int n, sum = 0, c, value;
 
   printf("\nEnter the number of integers you want to add :: ");

   scanf("%d", &n);
 
   printf("\nEnter %d integers :: ",n);

 
   for (c = 1; c <= n; c++)
   {
      scanf("%d",&value); 
      sum = sum + value;
   }
 
   printf("\nSum of entered integers :: %d",sum);

 
   return 0;
}

/*

Output ::

Enter the number of integers you want to add :: 5
Enter 5 integers :: 5 4 3 2 1
Sum of entered integers :: 15

*/

#include<stdio.h>
 
long factorial(int);
long find_ncr(int, int);
long find_npr(int, int);
 
main()
{
   int n, r;
   long ncr, npr;
 
   printf("\nEnter the value of n and r :: ");

   scanf("%d%d",&n,&r);
 
   ncr = find_ncr(n, r);
   npr = find_npr(n, r);
 
   printf("%dC%d = %ld\n", n, r, ncr);
   printf("%dP%d = %ld\n", n, r, npr);
 
   return 0;
}
 
long find_ncr(int n, int r)
{
   long result;
 
   result = factorial(n)/(factorial(r)*factorial(n-r));
 
   return result;
}
 
long find_npr(int n, int r)
{
   long result;
 
   result = factorial(n)/factorial(n-r);
 
   return result;
} 
 
long factorial(int n)
{
   int c;
   long result = 1;
 
   for( c = 1 ; c <= n ; c++ )
      result = result*c;
 
   return ( result );
}

/*

Output ::

Enter the value of n and r :: 5 2
5c2 = 10
5p2 = 20 

*/

#include <stdio.h>
 
int main()
{
  int n, c, k;
 
  printf("\nEnter an integer in decimal number system ::");

  scanf("%d", &n);
 
  printf("\n%d in binary number system is ::", n);
 
  for (c = 31; c >= 0; c--)
  {
    k = n >> c;
 
    if (k & 1)
      printf("1");
    else
      printf("0");
  }
 
  printf("\n");
 
  return 0;
}

/*

Output :

 Enter an integer in decimal number system :: 5

 5 in binary number system is :: 101
*/

#include <stdio.h>
 
long gcd(long, long);
 
int main() {
  long x, y, hcf, lcm;
 
  printf("Enter two integers :");
  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;
}

/*

Output :

Enter two integers : 5
10
Greatest common divisor of 5 and 10 = 5
Least common multiple of 5 and 10 = 10
*/

#include <stdio.h>
 
long gcd(long, long);
 
int main() {
  long x, y, hcf, lcm;
 
  printf("Enter two integers :");
  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);
  }
}

/*

Output :

Enter two integers :5
10
Greatest common divisor of 5 and 10 = 5
Least common multiple of 5 and 10 = 10
*/ 

#include<stdio.h>
 
long factorial(int);
 
int main()
{
  int n;
  long f;
 
  printf("Enter an integer to find factorial :");
  scanf("%d", &n); 
 
  if (n < 0)
    printf("Negative integers are not allowed.\n");
  else
  {
    f = factorial(n);
    printf("Factorial od %d = %d", n, f);
  }
 
  return 0;
}
 
long factorial(int n)
{
  if (n == 0)
    return 1;
  else
    return(n * factorial(n-1));
}

/*

Output :

Enter an integer to find factorial : 5
Factorial od 5 = 120
*/

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

/*

Output :

Enter a number to calculate it's factorial : 5

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

/*

Output :

Enter a number to calculate it's factorial: 5
Factorial of 5 = 120
*/

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

/*

Output: 

Enter an integer : 12345
Sum of digits of entered number = 15
*/

#include <stdio.h>
 
int main()
{
  int year;
 
  printf("Enter a year to check if it is a leap year : ");
  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;
}

/*

Output : #1

Enter a year to check if it is a leap year : 2010
2010 is not a leap year.
Output : #2
Enter a year to check if it is a leap year : 2012
2012 is a leap year.
Output : #3
Enter a year to check if it is a leap year : 2000
2000 is a leap year.
Output : #4
Enter a year to check if it is a leap year : 2100
2100 is not a leap year.
*/

#include <stdio.h>

int main()
{
  char ch;
  int flg;

  printf("Input a character : ");
  scanf("%c",&ch);
  flg=check_vowel(ch);
  if(flg==1)
  printf("%c is a vowel",ch);
  else
  printf("%c is not a vowel",ch);
  return 0;
}
int check_vowel(char a)
{

    if (a=='a'||  a == 'e'||  a == 'i'||  a == 'o'||  a == 'u'||a=='A'||  a == 'E'||  a == 'I'||  a == 'O'||  a == 'U')
       return 1;

    return 0;
}

/*

Output : #1

Input a character :A
A is a vowel


Output : #2
Input a character :x
x is not a vowel
*/

#include <stdio.h>
 
int main()
{
  char ch;
 
  printf("Input a character : ");
  scanf("%c", &ch);
 
  switch(ch)
  {
    case 'a':
    case 'A':
    case 'e':
    case 'E':
    case 'i':
    case 'I':
    case 'o':
    case 'O':
    case 'u':
    case 'U':
      printf("%c is a vowel.\n", ch);
      break;
    default:
      printf("%c is not a vowel.\n", ch);
  }              
 
  return 0;
}

/*

Output : #1

Input a character : A
A is a vowel. 
Input a character : x
x is not a vowel.
*/

#include <stdio.h>
 
int main()
{
  char ch;
 
  printf("Enter a character : ");
  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;
}

/*

Output : #1

Enter a character : A
A is a vowel
Output : #2
Enter a character : x
x is not a vowel
*/

#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("\nSum = %d",add);

   printf("\nDifference = %d",subtract);

   printf("\nMultiplication = %d",multiply);

   printf("\nDivision = %.2f",divide);

 
   return 0;
}

/*

Output :

Enter two integers :
10
5
Sum = 15
Difference = 5
Multiplication = 50
Division = 2
*/