Print array values which add up to the given data

#include<iostream>
using namespace std;
int main()
{
    int n = 5; int m =0;
    int givendata;
    int a[n]; 
    for (int i=0; i<n; i++){
    cin>>a[i];}
    cin>>givendata;
    if (m<n)
    {
        for (int i=0; i<n;i++)
        {
            int sum = a[n-i]+a[m];
            if (sum == givendata)
            {
                cout<<m<<" "<<n-i;
            }
        }
    }
    m = m+1;
    return 0;
}