Partition of an Integer + Number of partitions

Question

A partition of an integer n is a way of writing n as a sum of positive integers. For

example, for n=7, a partition is 1+1+5. I need a program that finds all the

Answer 1

How about this? Have an additional argument passed as reference for r, and increment r each time within the recursion block?

#include 
#include 

using namespace std;

void print (vector& v, int level){
    for(int i=0;i<=level;i++)
        cout << v[i] << " ";
    cout << endl;
}

void part(int n, vector& v, int level, int &r){
    int first; /* first is before last */

    if(n<1) return ;
    v[level]=n;
    print(v, level);

    first=(level==0) ? 1 : v[level-1];

    for(int i=first;i<=n/2;i++){
        v[level]=i; /* replace last */
        r++;
        part(n-i, v, level+1, r);
    }
}

int main(){
    int num;
    cout << "Enter a number:";
    cin >> num;

    int r = 0;
    vector v(num);

    part(num, v, 0, r);
    cout << "r = " << r << endl;
}

Output comes as:

Enter a number:5 
1 4 
1 1 3 
1 1 1 2 
1 1 1 1 1 
1 2 2 
2 3 
r = 6

Is this what you are looking for?