Comparison of the size of the value of type double in the C language

When the computer performs the calculation, it first allocates the address space according to the type of data, and after allocating the address, it first converts the input data into binary, and then performs the calculation. The value you enter a, which is logically correct, but is a pathological function from the point of view of the calculation algorithm, is a value that is prone to errors when the computer converts binary. As you can see from this, computers are not as smart as you.

The difference between the magnitudes and the equal is considered to be equal within a certain margin of error.

For example: double

d1,d2;

constdoubled

if(d1d2d

d1d2d);Consider d1 to be equal to d2, otherwise not equal.

No problem, you have to think about it this way, if to make a judgment, the actual operation is to judge the values of a-b with 0.

The first one obviously doesn't have any problems, and it's a double type.

The second comparison with integers, subtraction does not lose precision.

So there will be no problem with either of these.

When comparing the float and double types, because of the problem of the accuracy of the float double. Like what.

Probably and equally.

It should not be used directly. ab

and so on.

Rather, it is adopted. Make the difference between the two numbers, take the absolute value, and then follow.

The accuracy you specify is compared.

It can be obtained. The size of two double floats.

You can compare it like this, there won't be anything abnormal, put the top and bottom ** on it and take a look.

Double is a type of computer language, i.e., double-precision floating-point.

This data type is similar to a single-precision float, but is more accurate than float, and the amount of memory space it takes up at compile time varies from compiler to compiler, typically 4 bytes (32-bit) of memory space for single-precision floating-point numbers, and its numerical range is.

The double-precision type occupies 8 bytes (64-bit) of memory space and has a range of values. Declare a variable of type double: double puotient.

Initialize a variable of type double: puotient = ; double puotinet = 。

Floating-point data

1. Float type.

The compilation system allocates 4 bytes to each float-type variable, and the values are stored in the memory unit in the form of normalized binary number exponents.

2. Double type.

In order to expand the range of values that can be represented, a double-type data is stored with 8 bytes, and 15 significant digits can be obtained.

3. Long double type.

Different compilation systems handle the long double type differently, and Visual C++ handles the long double type in the same way as the double type, allocating 8 bytes.

Double data is a type of data used by computers, and double (double floating-point number) uses 64 bits (8 bytes) to store a floating point number.

Double can represent 15 or 16 significant digits in the decimal system, with negative values ranging from to and positive values ranging from to .

The maximum positive value of a double is or multiplied by 10 to the power of 308, and separating the false part of the numeric text from the exponential part of the numeric text with d causes the value to be treated as a double data type.

Double is a keyword in the C language, which stands for double-precision floating-point type, which occupies 8 bytes of memory space, the value range is ", the significant digit of double precision is fully guaranteed is 15 digits, and 16 bits is only part of the value***.

In C, float and double are both floating-point numbers. The difference is that the range represented by double is larger than that of float, and the range of decimal parts is also higher than that of float.

For example, the number Pi, if expressed as a float, can only be accurate to 6 decimal places at most. Double, on the other hand, is accurate to about 15 decimal places.

The exact number depends on the compiler used, but there is not much difference between the compilers of each machine.

As for the integer part, the range of the integer part represented by the float is already large enough, and it can be represented to the trillion level, which is already boundless. The range of integers represented by double is even larger. In actual development, except for a few high-precision fields, basically, the use of float is sufficient.

1. The range of negative values is to ;

2. The range of positive values is to .

Float and double are both floating-point data types in C++, and the difference between the three is:

1. The accuracy is different.

The floating-point type is a single-precision floating-point number, and the double-type is a double-precision floating-point number.

2. Allocate storage space.

The C++ compiler allocates 4 bytes for floating-point types and 8 bytes for two-type.

3. The number of significant bits is different.

float can provide 6 significant digits, and double can provide 15 significant digits.