Chapter 4: Problem 9

What statement do you use in pseudocode to write a dual alternative decision structure?

Short Answer

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Answer: A dual alternative decision structure in pseudocode can be written using the IF, THEN, ELSE, and END IF keywords. It starts with the IF keyword followed by a condition. Then, write statements for when the condition is true, followed by the ELSE keyword. Write statements for when the condition is false, and finally, close the structure with the END IF keyword.

Step by step solution

Example of Dual Alternative Decision Structure in Pseudocode

A dual alternative decision structure in pseudocode can be written using the IF, THEN, ELSE, and END IF keywords. Here's a general format for an if-else statement in pseudocode: ``` IF condition THEN statements to execute if condition is true ELSE statements to execute if condition is false END IF ```

Write IF keyword followed by a condition

Start the decision structure with the IF keyword, followed by the condition that needs to be checked. This condition can be a comparison between two values, an expression, or based on any other situation that could result in true or false. Example: ``` IF age >= 18 THEN ``` Here, the condition is checking if the age is greater than or equal to 18.

Write statements for when the condition is true

After the condition, write the statements that will be executed if the condition is true. These statements should be indented to convey that they are part of the IF clause. Example: ``` IF age >= 18 THEN ALLOW to vote ``` Here, if the age is greater than or equal to 18, the person is allowed to vote.

Write ELSE keyword

To handle the case when the condition is false, use the ELSE keyword. This should be in line with the IF keyword. Example: ``` IF age >= 18 THEN ALLOW to vote ELSE ```

Write statements for when the condition is false

After the ELSE keyword, write the statements that will be executed if the condition is false. As with the true condition statements, these should be indented. Example: ``` IF age >= 18 THEN ALLOW to vote ELSE DO NOT ALLOW to vote ``` Here, if the age is less than 18, the person is not allowed to vote.

Write END IF keyword to close the structure

Finally, complete the dual alternative decision structure by adding the END IF keyword. This tells the program that the decision structure is complete. Example: ``` IF age >= 18 THEN ALLOW to vote ELSE DO NOT ALLOW to vote END IF ``` Now the pseudocode demonstrates a dual alternative decision structure, which effectively checks the age and either allows or disallows voting based on the condition.

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What statement do you use in pseudocode to write a dual alternative decision structure?

Short Answer

Step by step solution

Example of Dual Alternative Decision Structure in Pseudocode

Write IF keyword followed by a condition

Write statements for when the condition is true

Write ELSE keyword

Write statements for when the condition is false

Write END IF keyword to close the structure

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