Page 330 - CITS - Computer Software Application -TT

COMPUTER SOFTWARE APPLICATION - CITS

Sometimes, it’s necessary to verify if the next value we’re about to read is of a specific data type or if the input has
reached its end (EOF marker encountered).
To accomplish this, we can utilise the hasNextXYZ() functions, where XYZ represents the type we are interested
in. These functions return true if the Scanner has a token of the specified type, and false otherwise. For example,
in the code below, we have employed hasNextInt() to check for an integer input. To check for a string, we use
hasNextLine(), and for a single character, we use hasNext().charAt(0)
Let’s review a code snippet for reading numbers from the console and calculating their mean
// Java program to read some values using Scanner
// class and print their mean.
import java.util.Scanner;

public class ScannerDemo2 {
public static void main(String[] args)
{
// Declare an object and initialise with
// predefined standard input object

Scanner sc = new Scanner(System.in);
// Initialize sum and count of input elements
int sum = 0, count = 0;
// Check if an int value is available
while (sc.hasNextInt()) {

// Read an int value
int num = sc.nextInt();
sum += num;
count++;

}
if (count > 0) {
int mean = sum / count;
System.out.println(“Mean: “ + mean);
}
else {

System.out.println(
“No integers were input. Mean cannot be calculated.”);
}
}

}
This Java program reads integer values from the standard input using the Scanner class and calculates their
mean (average). Here’s a breakdown of how the program works:
1 It imports the Scanner class to facilitate user input.
2 In the main method
• It creates a Scanner object sc to read input from the standard input stream (System.in).

• Initialises two variables, sum and count, to keep track of the sum of input values and the count of input
values, respectively.

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CITS : IT&ITES - Computer Software Application - Lesson 78 - 84

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