A data type is simply the range of data a certain variable falls in.
Such as
an integer is any whole number between -32767 to 32768 (I'm not 100% on the range)
so the data type for 13 is int per se
a float is and number with a decimal such as 123.854
a char is any alpha numeric (Letter or number or some special chars)
a bool (in c++) is boolean so it can only be true or false