Variables and Constants

 

In C++, variables are used to store and manipulate data in a program. A variable is a named storage location that holds a value of a specific data type. The data type of a variable determines the type of value it can store, such as an integer, a floating-point number, or a character.

There are several ways to declare a variable in C++:

int myAge;
float myGPA;
char myGrade;

Here, "myAge" is declared as an integer variable, "myGPA" is declared as a floating-point variable, and "myGrade" is declared as a character variable.

It is also possible to initialize a variable when it is declared by assigning a value to it, like this:

int myAge = 25;
float myGPA = 3.5;
char myGrade = 'A';

In addition to variables, C++ also has constants. Constants are similar to variables, but their value cannot be changed after they are initialized. Constants are declared using the keyword "const" before the variable name.

const int DAYS_IN_WEEK = 7;
const float PI = 3.14159;

Here, "DAYS_IN_WEEK" is a constant integer variable with a value of 7, and "PI" is a constant floating-point variable with a value of 3.14159.

In general, it is a good practice to use constants instead of "magic numbers" in code, as it makes code more readable, understandable, and maintainable.