Comparing Cell Phone plans c++ - c++

Question

I'm new here. Sorry if I'm not posting correctly. My program is comparing cell phone plans based on minutes. I want to know how I can compare plans to determine the best plan for the money. I believe I should be using minimum functions for this, but I'm honestly stuck. My code is below. Is it possible to find the minimum value from 3 separate functions? I'm not looking for an answer, but maybe an example or an article how to do so. Thanks!
#include<iostream>
using namespace std;
void companyA();
void companyB();
void CompanyC();
int min(); // I want to use this to find my minimum
int numEmployees;
int avgMin;
double totalCost;
// double bestChoice; Not used yet
int main()
{
double newMin;
cout << "Please enter number of employees." << endl;
cin >> numEmployees;
cout << "Please enter average minutes used by each employee. " << endl;
cin >> avgMin;
if (numEmployees < 0)
{
cout << "Incorrect value. Please enter positive number of employees." << endl;
cin >> numEmployees;
}
else if (avgMin < 0)
{
cout << "Incorrect value. Please enter positive number of minutes. " << endl;
cin >> avgMin;
}
cout << "\nStandard Packages" << endl;
cout << "Company A: For $29.99 per month, 450 minutes are included. Additional minutes are $0.35 per minute." << endl;
cout << "Company B: For $49.99 per month, 900 minutes are provided. Additional minutes are $0.30 per minute." << endl;
cout << "Company C: For $59.99 per month, unlimited minutes are provided." << endl;
companyA();
companyB();
companyC();
cout << "\nBased on the number of employees and average minutes used, " << x << "is the best choice." << endl;
system("pause");
return 0;
}
void companyA()
{
if (avgMin <= 450)
{
totalCost = 29.99*numEmployees;
cout << "\nCompany A will cost an $" << totalCost << " a month for " << numEmployees << " employee(s)." << endl;
}
else if (avgMin > 450)
{
totalCost = (avgMin-450)*0.35+29.99;
cout << "\nCompany A will cost an $" << totalCost << " a month for " << numEmployees << " employee(s)." << endl;
}
}
void companyB()
{
if (avgMin <= 900)
{
totalCost = 49.99*numEmployees;
cout << "Company B will cost an $" << totalCost << " a month for " << numEmployees << " employee(s)." << endl;
}
else if (avgMin > 900)
{
totalCost = (avgMin - 900)*0.30 + 49.99;
cout << "Company B will cost an $" << totalCost << " a month for " << numEmployees << " employee(s)." << endl;
}
}
void companyC()
{
totalCost = 59.99*numEmployees;
cout << "Company C will cost an $" << totalCost << " a month for " << numEmployees << " employee(s)." << endl;
}

Answer 1

I don't know if this is what you're looking for.
void minimum(double numEmployees, double avgMin);
double minimumCompany(double x, double y, double z);
void minimum(double numEmployees, double avgMin)
{
double totalCostA, totalCostB, totalCostC, minimumTotal;
string choice;
if (avgMin <= 450)
{
totalCostA = 29.99 * numEmployees;
cout << "\nCompany A will cost an $" << totalCostA << " a month for " << numEmployees << " employee(s)." << endl;
}
else if (avgMin > 450)
{
totalCostA = (avgMin - 450) * 0.35 + 29.99;
cout << "\nCompany A will cost an $" << totalCostA << " a month for " << numEmployees << " employee(s)." << endl;
}
if (avgMin <= 900)
{
totalCostB = 49.99*numEmployees;
cout << "Company B will cost an $" << totalCostB << " a month for " << numEmployees << " employee(s)." << endl;
}
else if (avgMin > 900)
{
totalCostB = (avgMin - 900)*0.30 + 49.99;
cout << "Company B will cost an $" << totalCostB << " a month for " << numEmployees << " employee(s)." << endl;
}
totalCostC = 59.99*numEmployees;
cout << "Company C will cost an $" << totalCostC << " a month for " << numEmployees << " employee(s)." << endl;
minimumTotal = minimumCompany(totalCostA, totalCostB, totalCostC);
if (minimumTotal == totalCostA)
{
choice = "Company A";
}
else if (minimumTotal == totalCostB)
{
choice = "Company B";
}
else
{
choice = "Company C";
}
cout << "\nBased on the number of employees and average minutes used, " << choice << " is the best choice." << endl;
}
double minimumCompany(double x, double y, double z)
{
double minimum = x;
if (y < minimum ) {
minimum = y;
}
if (z < minimum) {
minimum = z;
}
return minimum;
}
int main()
{
double numEmps, averageMin;
bool isValid = true;
while (isValid)
{
cout << "Please enter number of employees." << endl;
cin >> numEmps;
cout << "Please enter average minutes used by each employee. " << endl;
cin >> averageMin;
if ((numEmps < 0))
{
cout << "Please enter number of employees. " << endl;
cin >> numEmps;
isValid = true;
}
else
{
isValid = false;
}
if ((averageMin < 0))
{
cout << "Please enter average minutes used by each employee. " << endl;
cin >> numEmps;
isValid = true;
}
else
{
isValid = false;
}
}
cout << "\nStandard Packages" << endl;
cout << "Company A: For $29.99 per month, 450 minutes are included. Additional minutes are $0.35 per minute." << endl;
cout << "Company B: For $49.99 per month, 900 minutes are provided. Additional minutes are $0.30 per minute." << endl;
cout << "Company C: For $59.99 per month, unlimited minutes are provided." << endl;
minimum(numEmps, averageMin);
system("pause");
return 0;
}