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Java : Flip Boolean Value By String | Java Programs

Java program to flip the boolean, the assigngment to find boolean is pretty simple, here we validate boolean value in Java in multiple ways to make it easy for you.

This code is for flipping a boolean word represented by a string to its opposite or reverse value in Java language.

  • The problem here is to flip a boolean word represented by a string to its reverse or opposite value. For example : changing a string having value true to false or vice versa.
  • Our constraint here is pre-defining the values of the strings that are to be flipped to boolean words (true or false) only.
  • The input here is that of either of the two strings namely String a or String b each representing a boolean i.e. true or false.
  • The output here is the flipped boolean value depending on the input string. Boolean value false is returned for an input of String a (a=”true”) and vice versa.

Output:

  • Solution :
    1. In the main method, String a is initialized to the value true and String b is initialized to the value false.
    2. Within the two print statements, the reverse method is called once per statement. To understand the statements that get printed out, we need to better understand what the method reverse does with the code it encapsulates.
    3. Within the first print statement, the reverse method is called and String a is passed as an argument to the method.
    4. The reverse method starts with a conditional statement which checks if the value of the parameter s (passed in as String a here) is equal to the value “true”.
    5. Since this condition is satisfied, the method returns a boolean value of false and hence the first print statement in the main method prints out the correctly flipped value i.e. false.

      Note : Using .equals() method in place of the == operator is recommended to check for string equality. String interning helps in certain cases to equate similar strings but it doesn’t always come in play while checking for equality.

    6. Within the second print statement, the  reverse method is called again and String b having the value false is passed to the reverse method. The conditional statement is not satisfied since the value false is not equal to true and hence the method returns a boolean value of true which is then printed out and the execution of the main method is completed.

Java Flip Boolean

This code is for flipping a boolean value to its opposite or reverse value by taking user input in Java language.

  • The problem here is to flip a boolean value input by a user to its reverse or opposite value. For example : changing a boolean having value true to false or vice versa.
  • Our constraint here is the limitation of accepting only boolean values as the user input to avoid the program from throwing exceptions.
  • The input here is either of the two boolean values i.e. true or false, any of which is provided by the user.
  • The output here is the flipped boolean value depending on the input value. Boolean value false is returned for a user input of boolean value true and vice versa.

Output:

  • Solution :
    1. In the main method, a new Scanner class object is initialized and a reference variable sc is set to represent the object. This class is used to take user input in Java. Scanner class is part of the java.util package and hence the import statement in the beginning is stated to import the functionality of the specified class.
    2. The print statement in the next line asks the user to enter a boolean value.
    3. The .nextBoolean() method is called by the Scanner object sc. This method reads a user input of a boolean value and stores it to the boolean variable bn.
    4. Within the print statement in the next line, the reverse method is called and the input boolean bn is passed in as the argument.
    5. The reverse method compares the parameter b (which represents the user input boolean bn) using a conditional statement to the boolean value true. It returns the boolean value false if this condition is satisfied and returns true if it is not satisfied.
    6. To better understand the reverse method, let us assume the user inputs the boolean value false. Since the conditional statement is not satisfied, it returns the value true, hence successfully flipping the input boolean value.
    7. The print statement in the next line of the main method prints out the successfully flipped boolean value.