Hello, I am currently writing a program that estimates Pi values using three different formulas pictured here: http://i.imgur.com/LkSdzXm.png .

This is my program so far:

``````#include<iostream>
#include<cmath>
#include<iomanip>
using namespace std;
int main()

{
double leibniz = 0.0; // pi value calculated from Leibniz

double counter = 0.0; // starting value

double eulerall = 0.0; // pi value calculated from Euler (all integers)

double eulerodd = 0.0; // value calculated from Euler (odds)

int terms;
bool negatives = false;

cin >> terms;
cout << fixed << setprecision(12); // set digits after decimal to 12

while(terms > counter){
leibniz = 4*(pow(-1, counter)) / (2*counter+1) + leibniz;
counter++;
eulerall = sqrt(6/pow(counter+1,2)) + eulerall;
counter++;
eulerodd = (sqrt(32)*pow(-1, counter)) / (2*counter + 1) + eulerodd;
counter++;

cout << terms << " " << leibniz << " " << eulerall << " " << eulerodd <<endl;
}

if (terms < 0){
if(!negatives)
negatives=true;
cout << "There were " << negatives << " negative values read" << endl;
}
return 0;
}
``````

The sample input file that I am using is:
1
6
-5
100
-1000000
0

And the sample output for this input file is:

``````     1 4.000000000000 2.449489742783 3.174802103936
6 2.976046176046 2.991376494748 3.141291949057
100 3.131592903559 3.132076531809 3.141592586052
``````

When I run my program all I get as an output is:

1 4.000000000000 1.224744871392 1.131370849898.

So as you can see my first problem is that the second and third of my equations are wrong and I can't figure out why. My second problem is that the program only reads the first input value and stops there. I was hoping you guys could help me figure this out. Help is greatly appreciated.

In your loop you are doing `counter++;` three times. Once is sufficient;
Also I would do the square root, after the loop.

Try this

``````#include<iostream>
#include<cmath>
#include<iomanip>
using namespace std;
int main()
{
double leibniz = 0.0; // pi value calculated from Leibniz
double eulerall = 0.0; // pi value calculated from Euler (all integers)
double eulerodd = 0.0; // value calculated from Euler (odds)

double counter = 0.0; // starting value

int iter;

cin >> iter;
if (iter <=0 || iter >= 1e6 ) {
cout << "Invalid input, default precision will be set to 100 iterations" << endl;
iter = 100;
}

int i = 1;
while(counter <= iter){
leibniz = 4*(pow(-1, counter)) / (2*counter+1) + leibniz;
eulerall += 6/pow(counter+1,2);
eulerodd += 1/pow(i,3);
i += 2;
counter++;
}
eulerall = sqrt(eulerall);
eulerodd = pow(eulerodd*32,0.3333);

cout << "- Leibniz: " << setprecision(25) << leibniz << endl;
cout << "- Euler 1: " << setprecision(25) << eulerall << endl;
cout << "- Euler 2: " << setprecision(25) << eulerodd << endl;

return 0;
}
``````
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