Thread: Valid ticket id

String must be 6 characters, first 3 must be letters, last 3 must be digits

Here is my code:

import java.util.Scanner;
 
public class ValidTicket {
	public static void main (String[] args){
		Scanner in = new Scanner (System.in);
		String id;
		int c=' ',i;
		int letterCount=0, digitCount=0;
		System.out.printf("Enter ticked id\n");
		id= in.nextLine();
 
		if (id.length() != 6)
		{
			System.out.printf("Invalid ticket id\n"); 
		}
		else if (id.length() == 6)
		{
			//c= id.charAt(i);
			for (i=0; i<= id.length() -3; i++)//first 3 characters
			{		
				c= id.charAt(i);
				if (Character.isUpperCase(c) || Character.isLowerCase(c))
				{
					letterCount++;
				}
			}
			for(i=0; i> id.length() -3; i++)//last 3 characters
			{
				c= id.charAt(i);
				if (Character.isDigit(c))
				{
					digitCount++;			
				}
			{		
		}// end if
 
	    if (letterCount == 3 && digitCount==3)
	    {
	    	System.out.printf("Valid ticket id\n");
	    }
	    else 
	    	System.out.printf("Invalid ticket id\n");
	    }
 
}}}

However when I run my program, it does not work:
After I enter the string nothing happens.


Please help

Even when i format the nesting same problem: The code just stops executing after entering user input

import java.util.Scanner;
 
public class ValidTicket {
	public static void main (String[] args){
		Scanner in = new Scanner (System.in);
		String id;
		int c=' ',i;
		int letterCount=0, digitCount=0;
		System.out.printf("Enter ticked id\n");
		id= in.nextLine();
 
		if (id.length() != 6)
		{
			System.out.printf("Invalid ticket id\n"); 
		}
		else if (id.length() == 6)
		{
			//c= id.charAt(i);
			for (i=0; i<= id.length() -3; i++)//first 3 characters
			{		
				c= id.charAt(i);
				if (Character.isUpperCase(c) || Character.isLowerCase(c))
				{
					letterCount++;
				}
			}
			for(i=0; i> id.length() -3; i++)//last 3 characters
			{
				c= id.charAt(i);
				if (Character.isDigit(c))
				{
					digitCount++;			
				}
			{		
		}// end if
 
	    if (letterCount == 3 && digitCount==3)
	    {
	    	System.out.printf("Valid ticket id\n");
	    }
	    else 
	    	System.out.printf("Invalid ticket id\n");
	    }
 
}
}
}

Only the last 3 brackets are changed, nothing else is required in the fomatting and yesssss it stops executing before it exits

You should look up regular expressions. It will help you immensely with this.
Specifically, the matches method of the string class: matches(java.lang.String)
Regular Expressions: Pattern (Java Platform SE 7)

A regular expressions you could use:

"abc123".matches("^[a-zA-Z]{3}[0-9]{3}$")

If you need clarification on anything feel free to ask

Norm is exactly right. There is a problem with the incorrect use of braces, which would become obvious once you format/indent your code properly.

Besides that, there is also a problem with the second for loop:

for(i=0; i> id.length() -3; i++)//last 3 characters

To see the problem just add a println() after the for statement, e.g.,

for(i=0; i> id.length() -3; i++)//last 3 characters
{
    System.out.println("DEBUG: 2nd for loop");
    ...

Execute the program. If you provide it with a 6-character ticket ID, you should see the debug line being printed out (but will not - something you'll need to fix.)

Btw, if this is for your own exercise (i.e., not an assignment), the regular expression approach suggested by Parranoia can help make your code a lot more compact.

There is also another problem in the second for loop

for (i = 0; i > id.length() - 3; i++)

even correcting it

for (i = 0; i < id.length() - 3; i++)

You are still cycling through the first three characters rather than the last three

Thanks everyone.

Originally Posted by Java girl

Thanks everyone.

I gone through it and found that its compiling fine. But while executing showing just "Invalid ticket number". Let me go again through it.