Chapter 3, Problem 2E

Program Plan Intro

Variables:

A variable is a name given to the storage memory; the variables are declared with a data-type which represents the type of data needs to be stored in the variable.

• It contains a value which is to be stored in the memory.
• Those values are then used in a program and they undergo a set of operations.

Example:

int number = 10;

In the above line,

• The “int” represents the data type of the variable.
• The “number” represents the name of the variable.
• The “10” represents the value of the variable.

Rules to naming a variable:

To name a variable, it should undergo certain criteria; they are as follows:

• A variable name should not start with any numeric digits.
• The keywords are not to be named as a variable name.
• A variable does not include any special characters.
• A variable can contain alphabets, digits and underscore.

The variables that do not meet the above criteria are considered as illegal variables.

Explanation of Solution

Identifying the illegal variables:

Consider the variable “Int”,

• It is a legal variable, because a variable name can be a string.

Consider the variable “char”,

It is an illegal variable, because a char is a data type.

Consider the variable “6_05”,

• It is an illegal variable, because a variable name should not start with any numeric values.

Consider the variable “Calloc”,

It is a legal variable, because a variable name can be a string.

Consider the variable “Xx”,

It is a legal variable, because a variable name can be a string.

Consider the variable “alpha_beta_routine”,

It is a legal variable, because a variable name can be a string.

Consider the variable “floating”,

It is a legal variable, because a variable name can be a string.

Consider the variable “_1312”,

• It is an illegal variable, because a variable name should not start with any numeric values or underscore values.

Consider the variable “z”,

It is a legal variable, because a variable name can be a single character.

Consider the variable “ReInitialize”,

• It is a legal variable, because a variable name can be a string.

Consider the variable “_”,

• It is an illegal variable, because a variable name should not start with underscore values.

Consider the variable “A$”,

• It is an illegal variable, because a variable name should not contains special character.

Therefore, in the given variables, the illegal variables are “char”, “6_05”, “_1312”, “_” and “A$”.