C :

#include <stdio.h>
#include <stdlib.h>
int main()
{
	int a[6];
	scanf("%d%d%d",&a[0],&a[1],&a[2]);
	if(a[2]-a[1]==a[1]-a[0])
	{
		int i;
		for(i=3;i<6;i++)
			a[i]=a[i-1]+a[2]-a[1];
	}
	else if(a[2]/a[1]==a[1]/a[0])
	{
		int i;
		for(i=3;i<6;i++)
			a[i]=a[i-1]*(a[2]/a[1]);
	}
	printf("%d %d %d\n",a[3],a[4],a[5]);
	return 0;
}
//Author: ITProgrammer

C++ :

#include<iostream>
using namespace std;
int main(){ 
   int a,b,c;
   cin>>a>>b>>c;
   if(c - b == b - a){ 
      int t = c - b;
      cout<<c + t <<" " <<c + 2 * t <<" " << c + 3 * t<<endl;
   }else{ 
      int t = c / b;
      cout<<c * t <<" " <<c * t * t <<" " << c * t * t * t<<endl;
   }
   return 0;
}

Python :

a,b,c=map(int,input().split())
if c-b==b-a:
    t=c-b
    print(c+t,c+t+t,c+t+t+t)
else:
    t=c//b
    print(c*t,c*t*t,c*t*t*t)