# Alphanumeric input of 25 length

Problem

Write a program that will accept 25 alphanumeric characters. Accept the input 5 characters at a time and output them in all uppercase separated by a hyphen.

Example output: ASDFA-ASDFW-234AS-ALSDF-ASDFQ

Solution

Check that the input is alphanumeric and of length 5 using the regular expression

``````[a-zA-Z0-9]{5}
``````

If incorrect input we keep asking until the input is correct. Java solution:

``````// get input from keyboard
Scanner scanner = new Scanner(System.in);
StringBuilder all = new StringBuilder();
// x = 0...4 since question wants 5 strings
for (int x = 0; x < 5; x++) {
System.out.print("> ");
String five = scanner.next();
while (!five.matches("[a-zA-Z0-9]{5}")) {
// has to be alphanumeric with five length (keep asking if incorrect)
System.out.print("Input must be alphanumeric and of five length." +
"\n> ");
five = scanner.next();
}

all.append(five);
if (x != 4) {
// don't append - after last string
all.append('-');
}
}

// question asks for all caps
System.out.println("OUTPUT: " + all.toString().toUpperCase());
}
``````