Why use double instead of long?
Table of Contents
Why use double instead of long?
The type double provides at least as much precision as float, and the type long double provides at least as much precision as double. The set of values of the type float is a subset of the set of values of the type double; the set of values of the type double is a subset of the set of values of the type long double.
Is double more precise than long?
In C and related programming languages, long double refers to a floating-point data type that is often more precise than double precision though the language standard only requires it to be at least as precise as double . As with C’s other floating-point types, it may not necessarily map to an IEEE format.
Can a long store a double?
We cannot store a double value into a long type variable without casting because the range of double is greater than long and that’s why we need to type cast.
How long is a double?
In this article
| Type Name | Bytes | Range of Values |
|---|---|---|
| float | 4 | 3.4E +/- 38 (7 digits) |
| double | 8 | 1.7E +/- 308 (15 digits) |
| long double | same as double | Same as double |
| wchar_t | 2 | 0 to 65,535 |
Is double slower than float?
Floats are faster than doubles when you don’t need double’s precision and you are memory-bandwidth bound and your hardware doesn’t carry a penalty on floats. They conserve memory-bandwidth because they occupy half the space per number.
How big is long double?
8 bytes
Windows 64-bit applications
| Name | Length |
|---|---|
| long | 4 bytes |
| float | 4 bytes |
| double | 8 bytes |
| long double | 8 bytes |
What has more precision than a double?
In computing, quadruple precision (or quad precision) is a binary floating point–based computer number format that occupies 16 bytes (128 bits) with precision at least twice the 53-bit double precision.
How much precision does a double have?
double is a 64 bit IEEE 754 double precision Floating Point Number (1 bit for the sign, 11 bits for the exponent, and 52* bits for the value), i.e. double has 15 decimal digits of precision.
What can a double store?
Double is more precise than float and can store 64 bits, double of the number of bits float can store. Double is more precise and for storing large numbers, we prefer double over float. For example, to store the annual salary of the CEO of a company, double will be a more accurate choice.
How much long long can store?
In this article
| Type Name | Bytes | Range of Values |
|---|---|---|
| long | 4 | -2,147,483,648 to 2,147,483,647 |
| unsigned long | 4 | 0 to 4,294,967,295 |
| long long | 8 | -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 |
| unsigned long long | 8 | 0 to 18,446,744,073,709,551,615 |
How much double can store?
Float vs Double: Head to head comparison
| Float | Double |
|---|---|
| Can store Up to 7 significant digits | Stores up to 15 significant digits |
| Occupies 4 bytes of memory (32 bits IEEE 754) | Occupies 8 bytes of memory (64-bits IEEE 754) |
| If more than 7 digits are present, value is rounded off | 7-15 digits are stored as they are |
Can a long double store a larger range of values?
In other words, yes, a long double may be able to store a larger range of values than a double. But it’s completely up to the compiler. For modern compilers on x64, Clang and GCC uses 16-byte double for long double while VC++ uses 8-byte double.
How many bytes does a long double take up?
A long double typically only uses 10 bytes, but due to alignment may actually take up 12 or 16 (depending on the compiler and options) bytes in a structure. The 10 byte long double provides a 64-bit mantissa; this is very convenient for when you want to store 64 bit integers in floating point without loss of precision.
What is the difference between double and long double in C?
Thus, this explains the main difference between double and long double. Another difference between double and long double is that double allocates 8 bytes to store data while long double allocates 12 bytes to store data. Moreover, long double provides more precision than double. Hence, this is also a difference between double and long double.
Why are there so many more longs than doubles?
* According to that link, it would seem that there are actually more longs, since some doubles are lost due to the way NaNs and other special numbers are represented. long is a signed 64-bit integer value and double is a 64-bit floating point value.