时间格式hh：mm：ss输入

Question

I am in a case when i am given two time formats hh:mm:ss to input.

I know that int variables exctract from cin until a non-integer is reached. This means that i can extract the hours easily, but then the character ":" would still be in the stream, which would cause a problem for the extraction of minutes.

I know i can use cin.ignore() but since i have to input two time formats, the code just for the input would result very long and not seem too good.

Just to give you an idea:

int h,m,s, h2,m2,s2;
cin>>h;
cin.ignore();
cin>>m;
cin.ignore();
cin>>s;
cin>>h2;
cin.ignore();
cin>>m2;
cin.ignore();
cin>>s2;

I know that cin automatically ignores whitespaces. Is there a way to make it automatically ignore a specific character (in this case, the character ":")?

Answer 1

An easy approach is create a colon() manipulator:

std::istream& colon(std::istream& in) {
    if ((in >> std::ws).peek() == ':') {
        in.ignore();
    }
    else {
        in.setstate(std::ios_base::failbit));
    }
    return in;
}

You can then just extract the ':' characters:

in >> h >> colon >> m >> colon >> s;

Obviously, I'd create an input operator for times so I could then read the two objects using

in >> time1 >> time2;

Answer 2

For my case also I need time input in HH:MM:SS format. I solved that ':' input by using it as a delimiter for getline() function. I have attached that portion of code here.

const char delim = ':';
string hr_s, min_s, sec_s;  
int hr, min, sec;

cout << "Enter HH:MM:SS : " << endl;
std::getline(cin, hr_s, delim);
std::getline(cin, min_s, delim);
std::getline(cin, sec_s);

hr = stoi(hr_s);
min = stoi(min_s);
sec = stoi(sec_s);

if ((hr_s.length() == 2) && (min_s.length() == 2) && (sec_s.length() == 2)&& (isValidTime(hr, min, sec)))
    {       
        cout << "Good Time Format" << endl;
    }

    else 
    {
        cout << "Bad Time format input"<< endl;
    }

The method to check the validity of the numbers input:

bool isValidTime(int hr, int min, int sec)
{return (((hr >= 0) && (hr < 24)) &&
    ((min >= 0) && (min < 60)) &&
    ((sec >= 0) && (sec< 60)));}

Note: this code has no effect unless the user input some other character instead of ':' . For other case it should be fine. I am not sure if I answered your question or not but I hope this is helpful.