why do we need data type in cpp

1 						  Data types in c++
2	Built-in                User Defined            Derived
3    ----------              -----------             ------------
4    void, int,			    structure,              array,
5	char, float,		    union,					function,
6    double, bool,		    enum,					pointer,
7    long long			    class,					reference
8    Wide Character		    typedef

1Data Type 										Size
2int (Integer) = 5, 6, 7							2
3float (Floating Value) = -3.67, 2.67			4
4double (Double of float) = -7.8746				8
5char (Character) = 	'a', 'b', 'A'				1
6string (Multiple chars) = "Hello World" 		No of Chars
7bool (Boolean) = true, false					true = 1, false = 0

1int myNum = 5;               // Integer (whole number)
2float myFloatNum = 5.99;     // Floating point number
3double myDoubleNum = 9.98;   // Floating point number
4char myLetter = 'D';         // Character
5bool myBoolean = true;       // Boolean
6string myText = "Hello";     // String