Input Validation

[Elyril]

Hey,
So, in my program I have to take a start time, the length of the call and the rate in order to output it to the user. The only problem I have is validating the input to make sure the start time doesn't go over .59 (HH.MM format) in any instance. I was thinking about just putting a '&& < 0.59' into the if statements, but then I thought it would hurt the first part. Or am I thinking wrong? Here's my code anyway...

#include <iostream>
#include <conio.h>

using namespace std;

int main() //Program to calculate how much long-distance calls would be for differing lengths of time and certain starting times
{
	float start;
	float rate;
	int minutes;
	//Call start times displayed as HH.MM
	cout << "Enter what time the call was started (in HH.MM format): ";
	cin >> start;
	
	if (start >= 00.00 && start <= 06.59)
	{ 
		rate = 0.05;
	}
	else if (start >= 7.00 && start <= 19.00)
	{
		rate = 0.45;
	}
	else if (start >=19.01 && start <= 23.59)
	{
		rate = 0.20;
	}

	cout << "\nNow enter how long the call was in minutes: ";
	cin >> minutes;
	
	cout << "\nThe charge for this phone call was $" << rate * minutes << ".";		

	_getch();
	return 0;
}

[LB]

You should not be storing time in numeric types. Numeric types are not appropriate for storing dates or times in a human-readable format. You can store each part of the time separately in numeric types, but what you are doing currently will only cause you more problems.

[Elyril]

So what do you mean? Should I just store HH and MM separately and then in the if/else if statements, just designate them sorta the same? Like...

int hh;
int mm;

if (hh >= 0 && hh <= 6 && mm >= 00 && mm <= 59)

[LB]

Yes, though be careful about starting a numeric literal with 0 - that makes the compiler treat it as octal instead of decimal.

[Elyril]

Another question, how would I have the user input the data because the input has to specifically in HH.MM form.

[LB]

You could validate it with regex if your compiler supports C++11, or you could just validate it by hand using std::isdigit. After you validate it, then you can just use a std::istringstream to read the number, ignore the period, and read the other number.