Showing posts with label ackerman. Show all posts
Showing posts with label ackerman. Show all posts

Sunday 31 July 2016

Ackermans function using Recursion

Recursion: Ackerman's Function


Write a program for Ackerman's function using Recursion

Ack(3,0) = ack(2,1)
                = ack(1, ack(2,0))
                = ack(1, ack(1,1))
                = ack(1, ack(0, ack(1,0)))
                = ack(1, ack(0, ack(0, 1)))
                = ack(1, ack(0, 2))
                = ack(1, 3)
                = ack(0, ack(1, 2))
                = ack(0, ack(0, ack(1, 1)))
                = ack(0, ack(0, ack(0, ack(1, 0))))
                = ack(0, ack(0, ack(0, ack(0, 1))))
                = ack(0, ack(0, ack(0, 2)))
                = ack(0, ack(0, 3))
                = ack(0, 4)

                = 5


#include<stdio.h>
double acker(int m, int n);

void main()
{
                int m, n;
                double a;
                printf("\nEnter the value of m and n:");
                scanf("%d %d", &m, &n);

                if(m<0 || n<0)
                                printf("\nEnter nonnegatives only");
                a = acker(m, n);
                printf("\n A(%d , %d) = %lf", m, n, a);
}

double acker(int m, int n)
{
                if( m == 0 )
                                return n+1;
                else if(n == 0)
                                return  acker((m-1), 1);
                else
                                return  acker( (m-1), acker(m, n-1) );

}
Output:
Enter the value of m and n:         3              0
A(3 , 0) = 5.000000