Extracting ints and chars together

[auk411]

Homework Statement

I need to know how, in C++, to extract 3 integers and 2 chars. In other words, I need to extract from the keyboard this data: HH:MM:SS, where the HH, MM, and SS are integers (standing for hours, minutes, and seconds). The two semicolons are chars. There are NO spaces, returns, other whitespaces. So when the user enters the appropriate numbers into HH:MM:SS how do I extract the information keeping the hours as the hours, the chars as the chars, minutes as the minutes, and seconds as the seconds.

Homework Equations

cin can't be the answer because it delimits using whitespace, and there is no whitespace. I also haven't been taught how to convert strings to ints. So I doubt that is the way the prof
wants us to go.

The Attempt at a Solution

 

[Mark44]

Here's the C style of doing this.

#include <stdio.h>
.
.
.
int hrs, mins, secs;
printf("Enter the time as HH:MM:SS.\n");
scanf(" %d:%d:%d", &hrs, &mins, &secs);
.
.
.

BTW, ':' is a colon. A semicolon is this character - ';'

 

[I like Serena]

The scanf-solution is my preferred solution, although I'd check if the return-value of scanf() equals 3 (the number of fields succesfully parsed).

Here's an alternate, more C++ like, solution:

int hrs, mins, secs;
char ch;
std::cout << "Enter the time as HH:MM:SS." << std::endl;
if (std::cin >> hrs >> ch >> mins >> ch >> secs)
{
   ...
}

This one is less neat, because it depends on the format of the input string to be correct.

[EDIT]Note that the more C++ like way of doing things is in this case is worse the the old way to do it!
Also note that the old C style way still works in C++![/EDIT]

 

[Grep]

Here's a fancy way of doing it by overloading the >> operator. All in all, a fairly elegant solution, IMO. The ignore method comes in handy. You can also overload the << operator to print it out, of course.

#include <iostream>
#include <iomanip>

class Time
{
public:
    int hours, minutes, seconds;
    friend std::istream &operator >> (std::istream &is, Time &t);
};

std::istream &operator >> (std::istream &is, Time &t)
{
        is >> t.hours;
        is.ignore(1,':');
        is >> t.minutes;
        is.ignore(1,':');
        is >> t.seconds;
        return is;
}

int main(int argc, char *argv[])
{
    Time t;
    std::cin >> t;

    std::cout << std::setw(2) << std::setfill('0') << t.hours << ":"
              << std::setw(2) << std::setfill('0') << t.minutes << ":"
              << std::setw(2) << std::setfill('0') << t.seconds << '\n';

    return 0;
}

 

[DeeNos]

One possible solution would be to use the cin function to read in the entire input as a string, and then use string manipulation techniques to extract the individual pieces of data (hours, minutes, seconds). You could then use the stoi function to convert the string representation of the integers to actual integer values. Alternatively, you could use the scanf function with the appropriate format specifier to directly read in the integers and chars from the keyboard. It is important to note that when using scanf, you will need to include a space in the format specifier before the semicolons to account for the lack of whitespace in the input. For example, your format specifier could be "%d:%d:%d ;%c ;%c" to correctly extract the data in the format of HH:MM:SS.