Introduction

C++ or Cpp is a programming language derived from c that is also considered as a middle-level programming language, due to the capability of handling hardware level and its human like readability. This makes it heavily powerful tool or a risky nightmare if the code is miss set.

Variables and Types

Cpp is a statically typed programming language, which means that the variables must be declared before being compiled. Cpp present the fallowing data types:

Numbers :

There are two types of numeric variables: integer (whole numbers) and floating point (decimals). The syntax for those is ease to show.

Integers

Integers are represented by the keyword int. Its size is usually 4 bytes. Meaning, it can store values from -2147483648 to 2147483647.

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#include <iostream>
using namespace std;
 
int main () {
   // number definition:
   int a =1;
   int b = 2.5;
     
   // number printing;
   cout << "a :" << a << endl;
   cout << "b :" << b << endl;
   return 0;
}

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a :1 
b :2

Floats and Doubles

Float and Double are represented by the keywords float and double. The size of float is 4 bytes and the size of double is 8 bytes. Hence, double has two times the precision of float.

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#include <iostream>
using namespace std;
 
int main () {
   // number definition:
   float a =1;
   float b = 2.5;
     
   // number printing;
   cout << "a :" << a << endl;
   cout << "b :" << b << endl;
   return 0;
}

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a :1.0 
b :2.5

Complex

For the complex numbers, the keyword complex accepts two parameters, the first is for the real part and the second one is for the imaginary part. In Cpp there is not a built-in functionality for handling complex math, a special library called complex is required

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#include <iostream>
#include <complex>
using namespace std::complex_literals;
 
int main () {
   // number definition:
   complex<double> a (1,0);
   complex<double> b (2,5);
     
   // number printing;
   cout << "a :" << a << endl;
   cout << "b :" << b << endl;
   return 0;
}

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a :(1,0) 
b :(2,5)

As shown another way to define variables is the easiest one, just write them down as it, they will be interpreted as their type.

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a = 1
b = 2.5
c = 3+5j
print(a, b, c)

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1, 2.5 3+5j

Characters

Cpp treats the letters and words differently, as single letter characters(char), and wide characters(wchar_t). In Cpp the principal difference in characters is that char is a byte and wchar_t is 2 bytes; it is used to represent characters that require more memory.

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#include <iostream>

using namespace std;
 
int main () {
   // char and strings definition:
   char a = 'h';
    
   // number printing;
   cout << "a :" << a << endl;
   return 0;
}

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a :h

As mentioned before, Cpp is a heritage from C, both of them are statically typed, which means you can declare a variable without assigning a value.

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#include <iostream>

using namespace std;
 
int main () {
   // variable definition:
   char x ;
   
   //Variable assignment
   x = 7;

   // number printing;
   cout << "x :" << x << endl;
   return 0;
}

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x :7

Boolean

The logic behind programming is the binary system, but is also interpreted as true for 1 and false for 0. This binary-logic system is called Booleans in Cpp they are assignend with the keyword bool.

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#include <iostream>

using namespace std;
 
int main () {
   // variable definition:
   bool cond, val ;
 
   
   //Variable assignment
   cond = true;
   val = false;
   // number printing;
   cout << "the condition is " << cond << ", but the value is " << val << endl;
   return 0;
}

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the condition is 1, but the value is 0

void

C and Cpp have a peculiar variable type called void, and its only utility is to represent the void more exactly the absences of data. We will see its practicality later on.

Type modifiers

We can modify some of the fundamental data types by using type modifiers. There are 4 types modifiers in Cpp:

1. signed
2. unsigned
3. short
4. long

We can modify the following data types with the above modifiers:

int double char

This means that we can modify the memory usage of variables.

signed and unsined are used to assign positive only values or not.

long is used to expand the size of a variable.