The double Data Type
In the C language, a floating-point number can also be represented by another data type, called the double data type. In other words, you can specify a variable by the double keyword, and assign the variable a floating-point number.
The difference between a double data type and a float data type is that the former normally uses twice as many bits as the latter. Therefore, a double floating-point number is of at least 10 digits of precision, although the ANSI standard does not specify it for the double data type.
In Chapter, "More Operators," you'll learn to use the sizeof operator to obtain the length of a data type, such as char, int, float, or double, specified on your computer system.
