HackerRank Calculate the Nth term solution in c programming

In this HackerRank Calculate the Nth term solution in the c programming problem solution This challenge will help you learn the concept of recursion.

A function that calls itself is known as a recursive function. The C programming language supports recursion. But while using recursion, one needs to be careful to define an exit condition from the function, otherwise it will go into an infinite loop.

To prevent infinite recursion, if...else statement (or similar approach) can be used where one branch makes the recursive call and other doesn't.

void recurse() {

    .....

    recurse()  //recursive call

    .....

}

int main() {

    .....

    recurse(); //function call

    .....

}

Task

There is a series, S, where the next term is the sum of pervious three terms. Given the first three terms of the series, a, b, and c respectively, you have to output the nth term of the series using recursion.

HackerRank Calculate the Nth term problem solution in c programming.

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
//Complete the following function.

int find_nth_term(int n, int a, int b, int c) {
    if(n == 1)
        return a;
    else if (n == 2)
        return b;
    else if (n == 3)
        return c;
    
    return find_nth_term(n-1,a,b,c)+find_nth_term(n-2,a,b,c)+find_nth_term(n-3,a,b,c);
    
}

int main() {
    int n, a, b, c;
  
    scanf("%d %d %d %d", &n, &a, &b, &c);
    int ans = find_nth_term(n, a, b, c);
 
    printf("%d", ans); 
    return 0;
}

Second solution

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
//Complete the following function.

int find_nth_term(int n, int a, int b, int c) {
  //Write your code here.
    int tmp=0;
    if(n==1){
        return a;
    }
    else if(n==2){
        return b;
    }
    else if(n==3){
        return c;
    }
    tmp=c;
    c = find_nth_term(n-1,a,b,c);
    c += find_nth_term(n-2,a,b,c);
    c += find_nth_term(n-3,a,b,c);
    return find_nth_term(n--,c,tmp,b);

}

int main() {
    int n, a, b, c;
  
    scanf("%d %d %d %d", &n, &a, &b, &c);
    int ans = find_nth_term(n, a, b, c);
 
    printf("%d", ans); 
    return 0;
}