24 hour clock to 12 hour clock conversion - curly brace pairing issue

Question

I'm a beginner learning Java, and I'm trying to write a program to convert a user-inputted time to 12-hour time, or if it is supplied in 12-hour time format, to convert it to 24 hour time.

I have written some code, which worked as I tested it step by step, until I tried to modify to convert time from 12 hour to 24 hour format.

My code is below. I apologize for the redundancies and highly inefficient technique, but hey, I have to start somewhere. I believe my issue is in separating blocks of code, as I am trying to have a primary if statement to test whether the input ends with 'm' (i.e. if it's in 12 hour or 24 hour time when inputted), and then several nested if, else and else if statements.

import java.util.Scanner;

public class TimeConverter 
{

   public static void main ( String [] args )
{

   Scanner ask_user = new Scanner (System.in);
   System.out.println("Enter a time ([h]h:mm [am|pm]): ");
   String enter_time = ask_user.nextLine ();
   String am_pm = enter_time.substring(6);
   String am = ("am"); 
   String pm = ("pm");
   if (enter_time.substring(7).equals("m"))
{
   if (am_pm.equals(am))
{
   String am_12 = enter_time.substring(0, 2);
   String mins = enter_time.substring(2,5);
   int am_12i = Integer.parseInt(am_12);
   if (am_12i != 12)
{
   String am_sub = enter_time.substring(0,5); 
   System.out.println(am_sub);


} 
        else if (am_12i == 12)
{
        System.out.println("00" + mins);
}

}

        else if (am_pm.equals(pm))
{
        if (enter_time.equals("12:00 pm"))
{
        System.out.println(enter_time);
}
         else
{
         String minutes = enter_time.substring(2,5);
         String pm_add = enter_time.substring(0,2);
         int pm_add_i = Integer.parseInt(pm_add);
         int pm_add_fin = pm_add_i + 12;
         String pm_add_finS = Integer.toString(pm_add_fin);
         String converted_pmtime = (pm_add_finS + minutes);
         System.out.println(converted_pmtime);
 }


         else if (enter_time.substring(7) != ("m"))
 {
         String 24hour = enter_time.substring(0,2);
         String 12hourmins = enter_time.substring(2,7);
         int 24hournum = Integer.parseint(24hour);
         if (enter_time.equals("00:00"))
 { 
                                System.out.println("12" + 12hourmins);
 }
         else if (24hournum <= 11)
 {
         String hour = Integer.toString(24hournum);
         String minute = enter_time.substring(2,4);
         String fin = (hour + minute + "am");
 }

 }      
 }
 }

Answer 1

The real problem is that you didn't indent your code properly. Once you do that, it will be a lot easier for you to detect the problems by yourself.

A few bugs I found from just quickly looking at your code:

1. You are missing a few parentheses. (Again, proper indentation will help with this a lot.)

   if (enter_time.equals("12:00 pm"))
   {
       System.out.println(enter_time);
   }
   else
   {
       String minutes = enter_time.substring(2,5);
       String pm_add = enter_time.substring(0,2);
       int pm_add_i = Integer.parseInt(pm_add);
       int pm_add_fin = pm_add_i + 12;
       String pm_add_finS = Integer.toString(pm_add_fin);
       String converted_pmtime = (pm_add_finS + minutes);
       System.out.println(converted_pmtime);
   }
   
   
   else if (enter_time.substring(7) != ("m"))
   {
   

   You have a if statement. You then end the block with an else statement. There, however, is then and else if statement following the else. else if statements needs to be placed after the if statement and before the else statement. Either, the order of the else and else if statements are mixed up, or you are missing a closing bracket, }, after the else statement, and the else if part is really supposed to be part of the previous block.

   You are also missing a closing bracket at the end of your code.

2. Variables cannot start with a number. All your variables like 24hournum and 24hour are invalid.

3. In the following line, int 24hournum = Integer.parseint(24hour);, you use parseint instead of parseInt.

My advice is to:

1. Properly indent all your code. Most IDEs come with shortcuts to easily do this.
2. Read and research all error and warning messages shown in your console.
3. Debug and step through your code to find what part exactly is causing the error.