sumofarrayelements.cpp

#include<iostream>
using namespace std;
int sum(int *a,int n){

    // base case
    if(n==0){
        return 0;
    }

    // if(n==1){
    //     return a[0];
    // }

    // Recursive case
    // int chotiproblem=sum(a+1,n-1);//pure assumption
    // int badiproblem=a[0]+chotiproblem;
    // return badiproblem;
    return a[0]+sum(a+1,n-1);
}

int sum2(int *a,int n,int i){

    //base case
    if(i==n){
        return 0;
    }


    //recursive case
    // int chotiproblem=sum(a,n,i+1);
    // int badiproblem=a[i]+chotiproblem;
    // return badiproblem;
    return a[i]+sum2(a,n,i+1);


}
int sum3(int *a,int n){

    // Base Case
    if(n==0){
        return 0;
    }

    // Recursive case
    return sum3(a,n-1)+a[n-1];

}

int main(){
    int a[]={1,2,3,4,5,6};
    int n=sizeof(a)/sizeof(int);
    int x1=sum(a,n);
    cout<<"sum is "<<x1<<endl;
     int b[]={1,2,3,4};
   n=sizeof(b)/sizeof(int);
    int x2=sum2(b,n,0);
    cout<<"sum of x2 is "<<x2<<endl;
      int c[]={4,4,4,4};
   n=sizeof(c)/sizeof(int);
    int x3=sum3(c,n);
    cout<<"sum of x3 is "<<x3<<endl;
   
	return 0;
}