Chapter 5 exercises

E5.1
int a;
for(a=-5; a <= 5; a++) {
if (a >0)
System.out.println("The number "+a+" is positive");
if (a <0)
System.out.println("The number "+a+" is negative");
if (a==0)
System.out.println("The number "+a+" is neutral");
-----------------------------------------------------------------------------------------------------------------------------------------
E5.3
import java.util.Scanner;
public class P3_03 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
long number = input.nextInt();
input.close();
int num_digits = 1;
if (number < 0) number *= -1;
if (number >= 10 && number < 100)
{
num_digits = 2;
}
else if (number >= 100 && number < 1000)
{
num_digits = 3;
}
else if (number >= 1000 && number < 10000)
{
num_digits = 4;
}
else if (number >= 10000 && number< 100000)
{
num_digits = 5;
}
else if (number >= 100000 && number < 1000000)
{
num_digits = 6;
}
else if (number >= 1000000 && number < 10000000)
{
num_digits = 7;
}
else if (number >= 10000000 && number < 100000000)
{
num_digits = 8;
}
else if (number >= 100000000 && number < 1000000000)
{
num_digits = 9;
}
else if (number >= 1000000000 && number < 1000000000)
{
num_digits = 10;
}
else
{
System.out.println("Number greater than 10 billion.");
}
System.out.println("Num digits: %d", num_digits);
}
}
-----------------------------------------------------------------------------------------------------------------------------------------
E5.4
import java.util.Scanner;

public class P3d4 {
    public static void main(String[] args)
    {
        //initialize variables
        double number1 = 0;
        double number2 = 0;
        double number3 = 0;
        boolean failTest = false;

        Scanner in = new Scanner(System.in);

        //prompt and take input for the three numbers, flagging for
        //invalid doubles

        System.out.print("Please enter the first number: ");
        if (in.hasNextDouble())
        {
            number1 = in.nextDouble();
        }
        else
        {
            failTest = true;
        }

        System.out.print("Please enter the second number: ");
        if (in.hasNextDouble())
        {
            number2 = in.nextDouble();
        }
        else
        {
            failTest = true;
        }

        System.out.print("Please enter the third number: ");
        if (in.hasNextDouble())
        {
            number3 = in.nextDouble();
        }
        else
        {
            failTest = true;
        }