Minutes to return

[Army]

Exercise 4.16* Write a Time method public int timeInMinutes(): The executor tells the total number of minutes that have passed since midnight.

public class Time extends Object {
    private int itsHour;
    private int itsMin;
    private int timeMin;
    /** Create an object for the given hour and minute. If min
       * is negative, adjust the values to make 0 <= min < 60. */
       public Time (int hour, int min) {
           super();
           itsHour = hour;
           for (itsMin = min; itsMin < 0; itsMin = itsMin + 60){
           itsHour--;
          }
        } //=======================
        /** Return the time expressed in military time. */
        public String toString(){ 
            if (itsHour < 10) {
            return ("0" + itsHour) + itsMin;
        }else{
            return ("" + itsHour) + itsMin;
        }
    } //=======================
    /** Return the result of adding this Time to that Time. */
        public Time add (Time that){
            return that;
        } // left as an exercise
        
        public int timeInMinutes() {
            
        }
}

I don't know what to even start with.

[JosAH]

Suppose it's 15:20 (3:20pm); 15*60 + 20 minutes have passed since midnight ...

kind regards,

Jos

[Army]

I finished that but now I've run into this one and I can't finish it.

Exercise 4.17* Write a Time method public Time subtract (Time that): The executor returns a new Time object that is itself minus the parameter, e.g., 0720 subtract 1430 is 1650. If the difference is negative, add an extra 24 hours.

 public Time subtract (Time that) {
            Time sub = sub - that;
            if (sub < 0){
                
            }
            
    }

[Sierra]

"sub" ist not "yourself" (that is your "this" object in that method)... first you need to create a NEW object.
Then copy your own object information to the new object.
Then you subtract the time and check for its validity. All right so far?

[JosAH]

Go for the hh:mm notation again: 7:20 - 14:30 == -7:-10; the minutes are negative, so correct it: -8:50; the hours are negative, so correct it: 16:50. You can't just so sub-that where one (or both) of them is/are of type Time.

kind regards,

Jos

[Army]

I still don't understand....