Converting a input string (HH MM SS) to an int (HH:MM:SS)

[SubsidingHades]

I have to write a program that takes two different inputs (lets call them FirstTime & SecondTime) and then convert the two times to seconds , get the difference and display the result back into 24hour format, input must be (HH MM SS, i have this part correct) and then output must be (HH:MM:SS). Also the program must check which time is smaller before subtracting and i have to use assert macro to verify the times are legitimate times ((i Know this is something like assert (FirstTime >= 00 00 00 && FirstTime <= 23 59 59)) but it doesnt allow me to use >= and <= as it is still an integer

Here is my code sofar:

#include <iostream>
#include <time.h>
#include <cassert>
#include <string>

using namespace std;

int main()
{
string FirstTime, SecondTime:

cout << "Please enter the first time in a 24hour format (eg hh mm ss): ";
getline (cin, FirstTime);
assert (FirstTime >= 00 00 00 && FirstTime <= 23 59 59);
cout << "Please enter the second time in a 24hour formant (eg hh mm ss): ";
getline (cin, SecondTime);
assert (SecondTime >= 00 00 00 && SecondTime <= 23 59 59);
return 0;
}

[thmm]

I thinks it would be much easier if you read the times as integers.

#include <iostream>
#include <cassert>

using namespace std;

int main()
{
  int h1, m1, s1, h2, m2, s2;

  cout << "Enter first time in the format hh mm ss: ";
  cin >> h1 >> m1 >> s1;

  cout << "Enter second time in the format hh mm ss: ";
  cin >> h2 >> m2 >> s2;

  // check if times are valid

  assert((h1 >= 0) && (m1 >= 0) && (s1 >= 0));

  // do the same for 2. time
}

[SubsidingHades]

that actually makes it alot easier, i have been trying to get it to work with the string for almost 2 hours now.

So my next question is to convert it to seconds, i am going to assume i would make a new int for the first time and the second time as well as to get the difference

then i would say

FirstTime = (h1 * (60*60)) + (m1 * 60) + s1 to convert the first time into seconds and then the same for SecondTime, and then use a if function to check which one is smaller and then continue the subtraction but how do i convert the difference back to a 24h format which displays HH:MM:SS

[deleted account xyzzy]

how do i convert the difference back to a 24h format which displays HH:MM:SS

Using integer division (/) and modulus (%).

#include <iostream>

int main()
{
   int secs_hour   { 60 * 60 };
   int secs_minute { 60 };

   //           hours              minutes         seconds
   int time { (5 * secs_hour) + (15 * secs_minute) + 27 };

   int hours { time / secs_hour };

   // minutes and seconds are still "encoded" as a remainder
   int seconds { time % secs_hour };

   std::cout << "Hours: " << hours << '\n';

   // calculate for the minutes, seconds is the remainder
}

Hours: 5

[SubsidingHades]

Sweet, i got it right eventually thanks

[deleted account xyzzy]

Share what you've come up with, please. :)

And PLEASE use code tags. They make reading and commenting on source code MUCH easier.

http://www.cplusplus.com/articles/jEywvCM9/

[TheToaster]

You could also use regular expressions <regex> for this, but given that it is quite simple, it would be best to save regex for more complex string parsing.