When you do not want others (or yourself) to change existing variable values, use the const keyword (this will declare the variable as “constant”, which means unchangeable and read-only):
const int myNum = 15; // myNum will always be 15
myNum = 10; // error: assignment of read-only variable 'myNum'
You should always declare the variable as constant when you have values that are unlikely to change: Continue reading C++ Constants
All C++ variables must be identified with unique names.
These unique names are called identifiers.
Identifiers can be short names (like x and y) or more descriptive names (age, sum, totalVolume).
Note: It is recommended to use descriptive names in order to create understandable and maintainable code: Continue reading C++ Identifiers
To declare more than one variable of the same type, use a comma-separated list:
int x = 5, y = 6, z = 50;
cout << x + y + z;
Variables are containers for storing data values.
In C++, there are different types of variables (defined with different keywords), for example:
int – stores integers (whole numbers), without decimals, such as 123 or -123double – stores floating point numbers, with decimals, such as 19.99 or -19.99char – stores single characters, such as ‘a’ or ‘B’. Char values are surrounded by single quotesstring – stores text, such as “Hello World”. String values are surrounded by double quotesbool – stores values with two states: true or falseComments can be used to explain C++ code, and to make it more readable. It can also be used to prevent execution when testing alternative code. Comments can be singled-lined or multi-lined.
To insert a new line in your output, you can use the \n character:
#include <iostream>
using namespace std;
int main() {
cout << "Hello World! \n";
cout << "I am learning C++";
return 0;
}
You can also use another << operator and place the \n character after the text, like this : Continue reading C++ New Lines
You can also use cout() to print numbers.
However, unlike text, we don’t put numbers inside double quotes:
#include <iostream>
using namespace std;
int main() {
cout << 3;
return 0;
}
You can also perform mathematical calculations: Continue reading C++ Output Numbers
The cout object, together with the << operator, is used to output values and print text.
Just remember to surround the text with double quotes (""): Continue reading C++ Output
A computer program is a list of “instructions” to be “executed” by a computer.
In a programming language, these programming instructions are called statements.
The following statement “instructs” the compiler to print the text “Hello World” to the screen: Continue reading C++ Statements
Let’s break up the following code to understand it better:
#include <iostream>
using namespace std;
int main() {
cout << "Hello World!";
return 0;
}
Line 1: #include <iostream> is a header file library that lets us work with input and output objects, such as cout (used in line 5). Header files add functionality to C++ programs.
Line 2: using namespace std means that we can use names for objects and variables from the standard library. Continue reading C++ Syntax