How Do I Compute Sum Of Series 1+1/2-1/3+1/4-1-5.....1/N Recursively.

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I did this but it is returning the value of n. Tell me what to do???

int sum_of_series(int n)
{
static int value = 0;
static int answer;
static int answer1;
if(n == 1)
{
return 1;
}
else
{
answer = 1/1+sum_of_series(n-1);
return answer;
}
//return value;
}

Posted 10-Jan-15 19:38pm

Member 11345989

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Comments

Mohibur Rashid 11-Jan-15 2:21am

Your logic is wrong.One example is 1/1 will always return 1

2 solutions

Solution 1

Um. Have you looked at your code?

C++

answer = 1/1+sum_of_series(n-1);

Operator precedence says that is:

C++

answer = (1/1)+sum_of_series(n-1);

since you want:

1+1/2-1/3+1/4...

you need to start by using 1/N at some point... Then you can worry about the sign changing...

Posted 10-Jan-15 20:22pm

OriginalGriff

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George Swan · Accepted Answer · 2015-01-11T00:13:00

C#

public double sum_of_series(int n)
     {
         //the condition where recursion stops
         if (n == 1)
         {
             return 1;
         }
         double result;
         //if the divisor is even, sum the result else subtract it.
         if (n % 2 == 0)
         {
             result = this.sum_of_series(n - 1) + 1 / (double)n;
         }
         else
         {
             result = this.sum_of_series(n - 1) - 1 / (double)n;
         }

         return result;
     }