Gradient

#include <iostream>
using namespace std;

int main()
{
    int R1,G1,B1,R2,G2,B2,n;
    cin>>R1>>G1>>B1>>R2>>G2>>B2>>n;
    cout<<R1<<", "<<G1<<", "<<B1<<'\n';
    --n;
    int r=R2-R1,g=G2-G1,b=B2-B1;
    for(int i=1;i<=n;++i)
        cout<<(int)(R1+r*i/(float)n)<<", "<<(int)(G1+g*i/(float)n)<<", "<<(int)(B1+b*i/(float)n)<<'\n';
    return 0;
}