Question

The ability to read through Java™ code and predict the results, given specific inputs, is an extremely useful skill.

For this assignment, you will be analyzing the Java™ code in the linked zip file, and predicting the results given specific input.

Carefully read through the code line by line, then answer the following questions in a Microsoft^® Word document:

1. What is the output of the program as it is written?
2. What would the output of the program be if you assigned iAmHappy to false, num to 35, and numDayOfWeek to 5?
3. What would the output of the program be if you assigned the iAmHappy to 5, num to 50, and numDayOfWeek to 8?

**********************************************************************
* Program Summary: This program demonstrates these basic Java concepts:
* - defining variables of different types
* - if-then and if-then-else logic
* - switch logic
***********************************************************************/

package prg420_week2_supportingactivity;

public class PRG420Week2_AnalyzeAssignment {

public static void main(String args[]) {
  
// Example of if-then logic.
// If a condition is true, do something. If it is not true, do nothing.

boolean iAmHappy = true; // We can set a boolean variable to true or false (no quotes around either)
if (iAmHappy != false) { // We could also have said "iAmHappy == true" here and gotten the same result.
System.out.println("if-then example: I am happy today!");
}

// Example of if-then-else logic.
// If a condition is true, do something. If it is not true, do something else.

int num = 120; // The num variable is set to 120
if( num < 50 ) { // Since 120 is NOT less than 50
       // the compiler will skip the next line and go directly to "else"           
System.out.println("if-then-else example: num " + num + " is less than 50"); }
else { // Since 120 is greater than 50, the next code line will print.
System.out.println("if-then-else example: " + num + " is greater than or equal to 50");
}

// Example of switch logic.
// If a condition involving one of several pre-defined values is met, do something.
// If the value contains none of the pre-defined values, do something else (typically display an error).

int numDayOfWeek = 3; // Declare numDayOfWeek and assign it 3, meaning the third day of the week
String dayString; // Declare a variable of type String to hold the name of the day
switch (numDayOfWeek) { // Examine the value of numDayOfWeek variable
case 1: dayString = "Monday"; // If numDayOfWeek is 1, then it must be Monday
break;
case 2: dayString = "Tuesday"; // If numDayOfWeek is 2, then it must be Thursday
break;
case 3: dayString = "Wednesday"; // etc.
break;
case 4: dayString = "Thursday";
break;
case 5: dayString = "Friday";
break;
case 6: dayString = "Saturday";
break;
case 7: dayString = "Sunday"; // There are only 7 days in a week, but we will add the default case
break; // to handle unexpected data. In this example, we are setting numDayOfWeek in our code, but
// in a real program it would come from somewhere else--and might be < 1 or > 7 for all we know.
default: dayString = "Error! There are exactly 7 days in a week";
break;
}
System.out.println("switch example: Starting with Monday as day 1, the day of the week for " + numDayOfWeek + " is " + dayString + ".");
}


}

Answer 1

Answer:

a.

The output of the program is as follows:

if-then example: I am happy today !

if-then-else example: 120 is greater than or equal to 50

switch example: Starting with Monday as day 1, the day of the week for 3 is Wednesday.

Explanation:

1st part prints "I am happy today !" if the boolean variable iAmHappy is true

2nd part checks if 120 is greater than 50 or not then it prints that it is greater than 50 otherwise it would print the number is less than 50 if the number was less than 50

3rd part uses a switch statement to print the 3rd day of week as wednesday. The program passes numDayOfWeek as argument as switch and assigns a string of day according to the number.

b.

if variable iAmHappy is set to false ,then the program will not print anything and move on to next output.

if num is set to 35,then it will print "num 35 is less than 50"

if numDayOfWeek is set to 5 then it will print "Starting with Monday as day 1, the day of the week for 5 is Friday. "

The output is as follows:

if-then-else example: num 35 is less than 50
switch example: Starting with Monday as day 1, the day of the week for 5 is Friday.

c.

if we assign iAmHappy to 5,then the program will throw an error stating that you can't assign an integer variable to a boolean

if we set num to 50, it will print "50 is greater than or equal to 50"

if we set numDayOfWeek to 8, it will pick the default case of the switch statement to print i.e., "Error! There are exactly 7 days in a week."