iteration - how do you get the summation?

[amari ♥]

i need help with the following:

make a program that gets the summation of a given number e.g. 4+3+2+1

implement it using both iteration and recursion

ex. enter a positive number: 4
the sum is 10.

[Shankye]

Post your code .. We will help to solve probs ..

[sharathg.satya]

you can use the sum to 'n' terms formula to get your required result

[Shankye]

Recursion may be like this

sum(int n)
{
          if(n==0)
             return 0;
          else
             return n+sum(n-1);
}

iteration may be like this

while(i != 0)
{
      sum += i;
}

[sharathg.satya]

the loop in case of iteration is infinite
we have to decrement the value of 'i' so that it terminates when it becomes 0

[Shankye]

Oops sorry for the mistake..
Correct code may be like this

while(i != 0)
{
      sum += i;
      i--;
}

Hope code is correct now ..

[sharathg.satya]

haah now its right and thanks for correcting

[Shankye]

:-)

[sharathg.satya]

we also have a direct formula to calculate sum of n terms
i.e.., n*(n+1)/2
even using this we can do the problem of solving the sum of n terms

[Shankye]

Ya but he want a recursion and iteration based program ..

Mark it solved if problem solved ..