Given load (in erlang) and blocking probability, this script calculates the number of servers required.

erlang-calc.cpp

#include<iostream>

using namespace std;

int getServersCount(float prob, float load)
{
    long double B = 1.0;
    int m = 1;
    while(true) {
        B = 1 + B*m/load;
        if(B >= 1/prob)
            return m;
        m++;
    }
}



int main(void) 
{
    float prob = .02, load=3000;
    cout<<"Enter the value of probability and load respectively: ";
    cin>>prob>>load;
    cout<<"Number of servers required are: "<<getServersCount(prob, load)<<endl;
    return 0;
}