Question

I need a program in c++ the same as below code but

I want it to prompt the user to enter the number of elements

after that I want it to ask the user to enter the array elements

#include<algorithm>
#include<stdio.h>
#include<string.h>
#include<iostream>
using namespace std;
int a[50]={2,5,4,3};
bool x[100];
int N=4;//number of elements

  
int k=10;//target sum
int sum;//current target sum

int cmp(const void *a,const void *b)
{
return *(int *)b-*(int *)a;
}
void backtrace(int n)
{
if(sum>k)
return ;
if(sum==k)
{
for(int j=0;j<n;++j)
{
if(x[j])
cout<<a[j]<<" ";
}
cout<<endl;
return;
}
if(n==N)
return ;
for(int i=n;i<N;++i)
{
if(x[i]==false)
{
x[i]=true;
sum+=a[i];
backtrace(i+1);
x[i]=false;
sum-=a[i];
while(i<N-1 && a[i]==a[i+1])
i++;
}
}
}
int main()
{
sum=0;

memset(x,0,sizeof(x));
qsort(a,N,sizeof(a[0]),cmp);
backtrace(0);
return 0;
}

Answer 1

#include<algorithm>
#include<stdio.h>
#include<string.h>
#include<iostream>
using namespace std;
int a[50];
bool x[100];
int N;//number of elements

  
int k=10;//target sum
int sum;//current target sum

int cmp(const void *a,const void *b)
{
    return *(int *)b-*(int *)a;
}
void backtrace(int n)
{
   if(sum>k)
   return ;
   if(sum==k)
   {
       for(int j=0;j<n;++j)
       {
           if(x[j])
               cout<<a[j]<<" ";
       }
       cout<<endl;
       return;
   }
   if(n==N)
       return ;
   for(int i=n;i<N;++i)
   {
       if(x[i]==false)
       {
           x[i]=true;
           sum+=a[i];
           backtrace(i+1);
           x[i]=false;
           sum-=a[i];
           while(i<N-1 && a[i]==a[i+1])
           i++;
       }
   }
}
int main()
{
    sum=0;
    cout<<"Enter no of elements: ";
    cin>>::N;//::N consider variable N as the global variable
    cout<<"Enter Array Elements: ";
    for(int i=0;i<N;i++){
        cin>>a[i];
    }
    memset(x,0,sizeof(x));
    qsort(a,N,sizeof(a[0]),cmp);
    backtrace(0);
    return 0;
}