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09/17/09 - Selection Statements add intelligence to programs
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 | Adding intelligence (decision-making) capability to your programs
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 | if (age >= 16) {
System.out.println("You're old enough to drive.");
}
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| if (age >= 16) {
System.out.println("You're old enough to drive.");
}
else {
System.out.println("Don't worry. Your time will come.");
}
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| if (score >= 90) {
grade = 'A';
}
else if (score >= 80) {
grade = 'B';
}
else if (score >= 70) {
grade = 'C';
}
else if (score >= 60) {
grade = 'D'
}
else {
grade = 'F';
}
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| Nested if-else statements
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| if (iValue >= 10) {
if (iValue <= 20) {
System.out.println(iValue + " is between 10 and 20");
}
else {
System.out.println(iValue + " is > 20");
}
}
else {
System.out.println(iValue + " is < 10");
}
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| Combining tests in if statements with && (logical-and)
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| if (iValue >= 10 && iValue <= 20) {
System.out.println(iValue + " is between 10 and 20");
}
else {
System.out.println(iValue + " is < 10 or " + iValue + " is > 20");
}
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| Combining tests in if statements with || (logical-or)
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| if (iValue < 10 || iValue > 20) {
System.out.println("Either " + iValue + " is less than 10 or greater than 20");
}
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| switch statements for testing specific integer or char values
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| switch (choice) {
case 'A':
doOptionA();
break;
case 'B':
doOptionB();
break;
case 'C':
doOptionC();
break;
default:
System.out.println("Unknown option");
}
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| Write code in main that takes 10 integers from the user and displays the largest, the smallest and the average of the 10 integers.
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| /**
* Get 10 values from user, find max, min and average.
*
* @author Chuck Iverson
* @version 9/17/09
*/
import java.util.Scanner;
public class ValueTest
{
public static void main(String [] args) {
Scanner keyboard = new Scanner(System.in);
int value;
int max = -9999999;
int min = 9999999;
double average;
int sum = 0;
for (int i = 1; i <= 10; ++i) {
System.out.print("Enter integer #" + i + ": ");
value = keyboard.nextInt();
if (value > max) {
max = value;
}
if (value < min) {
min = value;
}
sum += value;
}
System.out.println("The max value is " + max);
System.out.println("The min value is " + min);
System.out.println("The average value is " + sum/10.0);
}
}
/* sample run
Enter integer #1: 3
Enter integer #2: 5
Enter integer #3: -2
Enter integer #4: 17
Enter integer #5: 23
Enter integer #6: 98
Enter integer #7: -234
Enter integer #8: 2345
Enter integer #9: 345
Enter integer #10: 987
The max value is 2345
The min value is -234
The average value is 358.7
*/
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| The standard grading scale is:
Create a public char letterGrade(int score1, int score2, int score3) method that takes three test scores as parameters and returns the letter grade based on the table above. Create a main method that interactively gets the three test scores from the user and calls your letterGrade method and displays the result.
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| Write a method void displayDivisors(int number) that takes a positive integer as a parameter and displays each integer divisor of that parameter.
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| Write a method boolean isPrime(int number) that takes a positive integer as a parameter and returns true if the number is prime (has no integer divisors other than itself and 1) and false otherwise.
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| A new tax law has just been passed by the government: the first $6000 of income is free of tax, the next $15,000 is taxed at 10%, the next $30,000 is taxed at 20%, and the rest is taxed at 30%. Write an interactive program that prompts for a user's income and reports the corresponding tax.
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| The Fast Freight Shipping Company charges the following rates:
The shipping charges per 500 miles are not prorated. For example, if a 2-kg package is shipped 550 miles, the charges would be $2.20.
Create a public double shippingCharge(double weight, double distance) method that takes the weight of a package and the distance it is to be shipped as parameters and returns the correct shipping charge for the package. Create a main method that interactively gets the package weight and distance to be shipped from the user and calls your shippingCharge method and displays the result.
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