Find the Factorial of a number

Summary: Factorial is represented using '!', so five factorial will be written as (5!),n factorial as (n!).
n! = n*(n-1)*(n-2)*(n-3)...3.2.1 and zero factorial is defined as one i.e. 0! = 1.



Using While Loop

#include<stdio.h>
void main()
{
    int a,f,i;
    printf("Enter a number: ");
    scanf("%d",&a);
    f=1;
    i=1;
    while(i<=a)
    {
        f = f * i;
        i++;
    }
     printf("\nFactorial of %d is: %d",a,f);
}

Using For Loop

#include<stdio.h>
void main()
{
    int a,f,i;
    printf("Enter a number: ");
    scanf("%d",&a);
    f=1;
    for(i=1;i<=a;i++)
        f = f * i;
     printf("\nFactorial of %d is: %d",a,f);
}

Using Recursion

#include<stdio.h>
int fact(int);
int main(){
 int num,f;

 printf("\nEnter a number: ");
 scanf("%d",&num);

 f=fact(num);

 printf("\nFactorial of %d is: %d",num,f);
 return 0;
}

int fact(int n){
 if(n==1)
  return 1;
 else
  return(n*fact(n-1));
}

   

Output

Enter a number: 5

Factorial of 5 is: 120

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Spiral Matrix

#include <stdio.h>
#define R 3
#define C 3

void spiralPrint(int m, int n, int a[R][C])
{
    int i, k = 0, l = 0;

    /*  k - starting row index
        m - ending row index
        l - starting column index
        n - ending column index
        i - iterator
    */

    while (k < m && l < n)
    {
        /* Print the first row from the remaining rows */
        for (i = l; i < n; ++i)
        {
            printf("%d ", a[k][i]);
        }
        k++;

        /* Print the last column from the remaining columns */
        for (i = k; i < m; ++i)
        {
            printf("%d ", a[i][n-1]);
        }
        n--;

        /* Print the last row from the remaining rows */
        if ( k < m)
        {
            for (i = n-1; i >= l; --i)
            {
                printf("%d ", a[m-1][i]);
            }
            m--;
        }

        /* Print the first column from the remaining columns */
        if (l < n)
        {
            for (i = m-1; i >= k; --i)
            {
                printf("%d ", a[i][l]);
            }
            l++;
        }
    }
}

/* Program to test above functions */
int main()
{
    int a[R][C] = { {1,  2,  3},
                    {8,  9,  4},
                    {7,  6,  5}
    };

    spiralPrint(R, C, a);
    return 0;
}

   

Output
1 2 3 4 5 6 7 8 9

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Print the Multiplication Table

#include<stdio.h>

void main()
{
 int x=1,num,res;
 printf("Enter a Number : ");
 scanf("%d",&num);
 while(x<=10)
 {
   res=num*x;
   printf("\n%d x %d = %d",num,x,res);
   x++;
 } 
}

  

Output
Enter a Number : 6
6 x 1 = 6
6 x 2 = 12
6 x 3 = 18
6 x 4 = 24
6 x 5 = 30
6 x 6 = 36
6 x 7 = 42
6 x 8 = 48
6 x 9 = 54
6 x 10 = 60

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Print 1 to 10 using While Loop

#include<stdio.h>
#include<conio.h>
int main()
{
 int x=1;
 while(x<=10)
 {
   printf("\n%d",x);
   x++;
 }
 getch();
 return 0;
}

  

Output
  1
  2
  3
  4
  5
  6
  7
  8
  9
  10

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