'For Loop' output problem help

[vdarth53]

Question: Write a function named SumTo() that takes an integer parameter named nValue, and returns the sum of all the numbers from 1 to nValue.

I am not getting the correct output. Is there anything wrong in the logic? Please help


#include<iostream>

using namespace std;

int SumTo(int nvalue)
{

for(int iii=0; iii < nvalue; iii++)
{

nvalue= nvalue+iii;
}
return nvalue;
}


int main()
{

int nvalue;
cout << "Enter a number= ";
cin >> nvalue;

int sum;
sum= SumTo(nvalue);
cout << "the result is " << sum;
return 0;
}

[vlad from moscow]

int SumTo( int nvalue )
{
   int sum = 0;

   for( int i = 1; i <= nvalue; i++ )
   {
       sum += i;
   }
 
   return ( sum );
}

In fact the sum is equal to nvalue*(nvvalue + 1)/2

So the function could be written as

inline int SumTo( int nvalue ) { return ( nvalue * ( nvalue + 1 ) / 2 ); }

[vdarth53]

Thanks for the reply. I am aware about the sum of n numbers but, I had to use the 'For' loop specifically for this question.
Also, can you please tell me what was wrong in my logic. I am getting te result if I do it in paper but the console output is giving me -2147450875 !!! (say for first 5 numbers). What am I missing here?

[vlad from moscow]

You always increse nvalue. So iii will be always less than nvalue until nvalue will not become negative.

for(int iii=0; iii < nvalue; iii++)
 {
 
nvalue= nvalue+iii;
 }

[vdarth53]

Oh yeah. Absolutely Right. Got your point. Thanks :)