How to implement Recursion algorithm using C programming language

//Green line and line having double back slash are comments
//* function within function Logic is one of the beneficial example for    recursion*/

#include < stdio.h >     //preprocessor directive contain all predefine function                                   //codes

    main(void)    // Main start here
      {
          int index;
     
         index = 8;
      
         CountindexDown(index);//function call

      }  //Main Ends here



     CountindexDown( int count)  //Definition of function

        {
             count--;
                printf("The value of the count is %d\n",count);
             
             if (count > 0)
               CountDown(count);
            printf("Current value of count is %d\n",count);
        }

/*To verify the result or output paste the code in  codepad area and compile or run this*/

C program to calculate percentile of student array

/*calculate percentile of student...i used predefined numbers and students
we can take value from user at run time  also using input fucntion*/

#include<stdio.h>

int main() 

 {

       //a[0]=obtain marks of first student 

      int a[]={25,60,80,70,26} ; 

      int n=5 ;

      int i,j ;

     //n=no. of student int percent; int count; 

        for( i=0;i<=n-1;i++) 

           { 

                count=0; 

                for(j=0;j<=n-1;j++)

                  { 

                      if(a[i]>a[j]) 

                        { 

                           count=count+1; 

                        } 

                  } 

                percent = (count * 100) / (n-1) ; //logic to calculate percentile

                printf( "\n the percentile of a[%d] is %d", i, percent) ;

            } 

 } //end of main

Calculate percentile of Students in a class using C++

/*calculate percentile of student...i did hardcode
we can get the value at run time using input fucntion*/


#include<iostream.h>
using namespace std;

int main()
{
 //a[0]=first candidate and so on
    int a[]={25,60,80,70,26},n=5,i,j;//n=no. of candidate
    int percent;
    int count;
       for( i=0;i<=n-1;i++)
         { 
             count=0;
             for(j=0;j<=n-1;j++)
               { 
                   if(a[i]>a[j])
                    {
                       count=count+1;
                    }
                }

                     percent = (count * 100) / (n-1); 

               cout << "\n the percentile of " << " a ["<<i<<"] " << percent ;

          }
 
} //End of main

/*OUTPUT:-
1-the percentile ofa[0]0

2-the percentile ofa[1]50 

3-the percentile ofa[2]100 

4-the percentile ofa[3]75 

5-the percentile ofa[4]25
*/

C++ program to print decimal value of Keys appear in Keyboard

//Print decimal value of buttons appear in keyboard

#include<iostream.h> 

using namespace std;

 int main()

 { 

       int a; 

       char b; 

         for(a=0;a<=255;a++)

            { 

               b=(char)a;

               cout<<"\nASCII value of character=> "<<b<<" "<<a;

            } 

     return 0; 

}

/*:-output wiil be like:-
ASCII value of character   : 32

ASCII value of character '!' : 33 

ASCII value of character' " '   : 34 

ASCII value of character '#'  : 35 

ASCII value of character '$'  : 36 

ASCII value of character '%'  : 37 

*/

C program to print ASC|| value of character of keyboard

//C program to print ASC|| value of character of keyboard

#include<stdio.h> 

int main()
{ 

       int a; 

       for(a=0;a<=255;a++) 

          {

            printf("ASCII value of character %c: %d\n",a,a); 

          }

   return 0; 

}

/* OUTPUT */

C program to Concatnate two string or addition of two string

//Green lines shows they are commented

#include<stdio.h>  //header files
#include<string.h> //Header files
 
void main()  //starting of main
{
   char str1[100], str2[100];
 
   printf("Enter the first string\n");
   gets(str1);
 
   printf("Enter the second string\n");
   gets(str2);
 
   strcat(str1,str2);  //predefine function to perform concatnation
 
   printf("String obtained on concatenation is %s\n",str1);
 
} //End of main

C program to find Factorial of a positive number

/*Green color shows that its a comment*/
/*Programme to find factorial of a number*/

#include<stdio.h>

int main()
{
          int i , facto=1,num;
        printf("Enter your number\n");
        scanf("%d",&num);
   
          for(i=1;i<=num;i++)//logic to find factorial
          {
              facto=facto*i;
          }

        printf("Factorial of %d is=>%d",num,facto);  //Print output

} //End of main program