Hello, I have written a program for the sum of pi #include <cstdlib> #include <i

Question

Hello, I have  written a program for the sum of pi

#include <cstdlib>
#include <iostream>
#include <cmath>

using namespace std;

int main()
{
    double pi = 0;
    double i;
    int n;
    
    cout<<"This program approximates pi using an n-term series expansion."<<endl;
    cout<<"Enter the value of n>";
    cin>>n;
    cout<<endl;
    
    if(n <= 0)
    {
    cout<<""<<n<<" is an invalid number of terms."<<endl;
    cout<<endl;
    }
      else
      {
         for (double i = 1; i <= n; i++)
         {
         pi += pow(-1, i+1)*(4/(2*i-1));
         
         }
         cout.precision(20);
         cout<<"pi"<<"["<<n<<"]"<<" = "<<pi<<endl;
         cout<<endl;
     }
        
           
    return 0;
}

However, it only outputs the answers. it should be display just like the sample runs below.

pi[10] = 4[1 - 1/3 + 1/5 - 1/7 + 1/9 - 1/11 + 1/13 - 1/15 + 1/17 - 1/19] = 3.04183961892940146754

Can anyone help me with this issue? It's the only problem I have.

Explanation / Answer

Three things: First, change your calculation of secondTerm for the following:

This way, you are forcing it to be a double (otherwise, it would return an int, which we do not want). Second, change this line:

for this line:

That is because secondTerm holds the result of the division, not the denominator.

Third, move this line:

after the for loop, because that prints the final result, which you would do after you sum all the terms.Having that line inside the for is causing the line breaks. If you do this, you will need to move this line:

before the for loop, so the sum variable continues to exist afterwards.

If you do all this, the program will work fine (although it prints all the terms without any spaces between them).

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