Question

Assume the variable phone consists of a valid phone number with dashes, e.g., ###-###-####.

Complete the following statement that displays the prefix (digits 5 through 7).
System.out.println("The prefix is: " + _________________________________________________);

Answer 1

To display the prefix of a phone number formatted as ###-###-#### in Java, use the substring method: System.out.println("The prefix is: " + phone.substring(4, 7));. This code extracts digits 5 through 7, which is the prefix.

Step-by-step explanation:

The student has asked how to extract the prefix of a phone number from a string in the format ###-###-#### using Java. To accomplish this, we can use the substring method that is part of the String class in Java. This method allows us to extract a portion of a string by specifying the starting index (inclusive) and the ending index (exclusive).

Considering that the phone number is given in the format ###-###-####, the prefix which are the digits 5 through 7 corresponds to the second group of numbers. The substring method will take starting index 4 (since indices start with 0) and ending index 7. Therefore, to complete the statement and extract the prefix, we can use the following code:

System.out.println("The prefix is: " + phone.substring(4, 7));

The given code will successfully print out the prefix of the phone number stored in the variable phone.