I have this code here:

But I get the error message:

The operator < is undefined for the argument type(s)LocalTime, int

Why is that? How can I fix the code?

Here is the code again as text:

import java.time.LocalTime;

public class Services {
    public static void main(String[] args){
        LocalTime t = LocalTime.now();
        
        if (t >=0 && t<12){
            System.out.println("Good Morning!");
        }
        else if (t>=12 && t<18)
        {
            System.out.println("Good Afternoon!");   
        }
        else{
            System.out.println("Hello Neel ,how may I help you");  

               
        }
    }
}

CodePudding user response：

Comparing objects

You can not use < on anything else than primitives like int. Use compareTo instead.

Like first.compareTo(second), the result is either

• negative (if smaller),
• 0 (if equals) or
• positive greater 0 (if greater).

So the equivalent of to first < second would be first.compareTo(second) < 0.

Comparing LocalTime in particular

For the java.time API, there are also special methods like isBefore and isAfter which make this comparison even simpler.

LocalTime vs int

Also, you can not compare a high level object such as LocalTime to a plain int. Have a look at

LocalTime.of(12, 0)

and similar methods instead.

There are also some special pre-created constants, such as LocalTime.MIDNIGHT and LocalTime.NOON.

Putting everything together

If you follow both advices, the fixed code could look like:

LocalTime t = LocalTime.now();

if (t.isAfter(LocalTime.MIDNIGHT) && t.isBefore(LocalTime.NOON)) {
  System.out.println("Good Morning!");
} else if (t.isAfter(LocalTime.NOON) && t.isBefore(LocalTime.of(18, 0))) {
  System.out.println("Good Afternoon!");   
} else {
  System.out.println("Hello Neel, how may I help you"); 
}

Ideally you could also introduce a quick helper method such as

private static boolean isBetween(LocalTime start, LocalTime time, LocalTime end) {
  return time.isAfter(start) && time.isBefore(end);
}

to simplify the code further:

LocalTime t = LocalTime.now();

if (isBetween(LocalTime.MIDNIGHT, t, LocalTime.NOON)) {
  System.out.println("Good Morning!");
} else if (isBetween(LocalTime.NOON, t, LocalTime.of(18, 0))) {
  System.out.println("Good Afternoon!");   
} else {
  System.out.println("Hello Neel, how may I help you"); 
}

CodePudding user response：

The straightforward way to translate your code into something that works is

 LocalTime t = LocalTime.now();
 int h = t.getHour();

and then compare 'h'.

For more complicated cases, for example if you wanted to check whether it was before 12:30, look into constructions like

 t.isBefore(LocalTime.of(12, 30))

or possibly

 !LocalTime.of(12, 30).isAfter(t);

(The two differ in the decision of the exact time 12:30)

CodePudding user response：

    public static void main(String[] args) {
    
    LocalTime t = LocalTime.now();
    int h = t.getHour();
    if (h >= 0 && h < 12) {
        System.out.println("Good Morning!");
    } else if (h >= 12 && h < 20) {
        System.out.println("Good Afternoon!");
    } else {
        System.out.println("Hello Neel ,how may I help you");

    }
}

}This worked for me