Double is a data type used by computers. It uses 64 bits (8 bytes) to store a floating-point number. It can represent decimal 15 or 16 significant digits, and the absolute value range of the digits that can be represented is about:1.7x10-308 ~1.7x10308. IEEE754 customized the standard for it.

Double precision is a double precision floating point number.

The character type is 8-bit binary number;

The string is an array of 8-bit binary numbers;

Integer is a binary number of 16;

Long integer 32-bit binary number;

Double-precision type occupies 8 bytes (64 bits) of memory space, and its numerical range is-1.79769313486232e308 to 1.79 13486232e308.

Generally, single-precision floating-point numbers occupy 4 bytes (32 bits) of memory space, with values ranging from -3.4E38 to 3.4E38, and double-precision types occupy 8 bytes (64 bits) of memory space, with values ranging from-1.79769313486232e308 to1.

Extended data:

Double-precision floating-point type values can be converted to other types of integers or floating-point numbers, and vice versa. The last character of a double-precision floating-point constant can be added with "d" or "d". Its storage format is similar to floating point, the highest bit is sign bit, the second highest bit is exponent bit, and the last 52 bits are mantissa bit.

A double-precision type is a double-precision floating-point type. Compared with numerical model, it can provide higher numerical accuracy. It adopts floating-point type with fixed storage length, and each double-precision floating-point type data accounts for 8 bytes. Different from numerical data, its decimal point position is determined by the input data value and can only be used for fields in tables.

Reference source: Baidu Encyclopedia-Double precision floating-point type