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Chapter 1: Problem 25

A variable must be __________ before it can be used in a program.

Short Answer

Expert verified
Answer: A variable must be declared and initialized before it can be used in a program.

Step by step solution

01

Define the Concept of a Variable

A variable is a named memory location in a program that stores a value. It allows the programmer to represent and manipulate values by referring to the variable name. The name of the variable is used as an identifier to access or modify its value.
02

Identify the Action Required

Before using a variable in a program, the programmer must perform an action to ensure that it is ready for use. This action is called "declaration" or "initialization." In some programming languages, declaration and initialization are separate steps, while in others, they can be combined.
03

Declaration

Declaration is the process of telling the program that a variable exists and providing information about its data type (e.g., integer, float, string). This step does not assign a value to the variable, but it reserves memory for its future use.
04

Initialization

Initialization is the process of assigning an initial value to a declared variable. This step is essential because using a variable without assigning a value can lead to unpredictable behavior or errors in the program.
05

Answer

Therefore, a variable must be __declared and initialized__ before it can be used in a program.

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Most popular questions from this chapter

Draw hierarchy charts or flowcharts that depict the programs described below. (See Appendix D for instructions on creating flowcharts.) Sales Tax Design a hierarchy chart or flowchart for a program that calculates the total of a retail sale. The program should ask the user for: \- The retail price of the item being purchased \(-\) The sales tax rate Once these items have been entered, the program should calculate and display: \- The sales tax for the purchase \(-\) The total of the sale

What type of software controls the internal operations of the computer's hardware?

Words or names defined by the programmer are called __________.

Draw hierarchy charts or flowcharts that depict the programs described below. (See Appendix D for instructions on creating flowcharts.) Available Credit The following steps should be followed in a program that calculates a customer's available credit: 1\. Display the message "Enter the customer's maximum credit." 2\. Wait for the user to enter the customer's maximum credit. 3\. Display the message "Enter the amount of credit used by the customer." 4\. Wait for the user to enter the customer's credit used. 5\. Subtract the used credit from the maximum credit to get the customer's available credit. 6\. Display a message that shows the customer's available credit.

Questions \(33-35\) are programs expressed as English statements. What would each display on the screen if they were actual programs? The variable x starts with the value 0. The variable y starts with the value 5. Add 1 to x. Add 1 to y. Add x and y, and store the result in y. Display the value in y on the screen.
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