ProjectEuler Problem-12 Solution

Problem :

The sequence of triangle numbers is generated by adding the natural numbers. So the 7^th triangle number would be 1 + 2 + 3 + 4 + 5 + 6 + 7 = 28. The first ten terms would be:

1, 3, 6, 10, 15, 21, 28, 36, 45, 55, ...

Let us list the factors of the first seven triangle numbers:

 1: 1
 3: 1,3
 6: 1,2,3,6
10: 1,2,5,10
15: 1,3,5,15
21: 1,3,7,21
28: 1,2,4,7,14,28

We can see that 28 is the first triangle number to have over five divisors.
What is the value of the first triangle number to have over five hundred divisors?

Solution :

#include<iostream>
using namespace std;
#include<math.h>
#include<stdio.h>
#include<time.h>
#include<stdlib.h>
long long int calculate(long long int i)
{
 long long int sum=0,n;
 for( n=1;n<=i;n++)
 sum=sum+n;
 return sum;
}

int main()
{
 int divisor;
 long long int num,i=1,j;
 double s;
 while(1)
 {
  divisor=0;
  num=calculate(i);
            
                for(j=1;j<sqrt((double)num);j++)
                if(num%j==0)
                divisor++;
                 
                divisor*=2;
              
                s=sqrt((double)num);
                if(s*s==num)
                divisor++;
                
       if(divisor>500)
  break;
  i++;
 }
cout<<"\nAnswer:"<<num; 
 printf("\nEXECUTION TIME = %f\n",clock()/(float)CLK_TCK);
                system("pause");
return 0; 
}