About the difference between float and double

The variable types are different. float is a single-precision floating-point data. Double is a double-precision floating-point data.

C++ is the inheritance of the C language, which can not only carry out the process programming of the C language, but also carry out the object-based programming characterized by abstract data types, and can also carry out the object-oriented programming characterized by inheritance and polymorphism.

C++ excels at object-oriented programming as well as process-based programming, so C++ is based on the size of the problem it can adapt to.

Shortly after the first draft of the C++ standardization was completed, something happened that greatly expanded the C++ standard: Alexander Stepanov created the Standard Template Library (STL). STL is not only powerful, but also very elegant.

However, it is also very massive. After the adoption of the first draft, the committee voted and adopted the proposal to include STL in the C++ standard. STL's extensions to C++ go beyond the original definition of C++.

While the addition of STL to the standard was an important decision, it also slowed down the process of C++ standardization.

digitally. Just add 10 more digits after pi.

The number of bytes in memory is different, and the accuracy and range are different.

The precision of double is twice that of float, and it is better to use double when the precision required for the operation is higher or the number of digits is larger.

float is a single-precision floating-point type.

Bouble is a double-precision floating-point type.

Accuracy issues, there should be in the book.

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.

Hello, glad to be able to answer 1The range of representation is different, and the decimal range and integer range represented by double are larger than float; In memory, it takes up 8 bytes, and float in memory, which takes up 4 bytes. 3.

The accuracy is not the same, float is single precision, double precision is double precision. float is a floating-point data type, and double is a double-precision floating-point data type, and double is more accurate than float.

Differences: 1. The accuracy is different, float is single precision, double is double precision;

2. The range of decimals is different, and the range that double can represent is larger than that of float;

3. Double is in memory, accounting for 8 bytes, and float is in memory, accounting for 4 bytes.

float: float data type, which is used to store single-precision floating-point numbers or double-precision floating-point numbers. Floating-point numbers use the IEEE (Institute of Electrical and Electronics Engineers) format.

A single-precision value of the floating-point type has 4 bytes and includes a sign bit, an 8-bit binary exponent, and a 23-bit mantissa number. Since the high sequential bit of the mantissa is always 1, it is not stored in numeric form. This representation provides a range of float types approximately between .

double: double-precision floating-point type, this data type is similar to single-precision data type (float), but the accuracy is higher than float, and the memory space occupied by compilation varies according to different compilers, which is a variable type of double float data type, which represents real variables in C C++.

int—Integer.

double—Double-precision floating-point.

float—Single-precision floating-point.

int is an integer variable that stores the integer value as a base type, int is a 32-bit integer in a 32-bit device and a 64-bit integer in a 64-bit device.

float and double refer to decimal variables, float is a 32-bit value and double is a 64-bit value, and when using decimals, the compiler always infers them as a double type, not a float type. Therefore, if you don't need 64-bit precision, you need to declare the variable as float in the display.

intbyte4 numeric range: -2147483648 +2147483647

floatbyte 4, value range, one decimal place).

double bytes, 8 numeric ranges, decimals).

1. The types of variables are different.

float is a single-precision floating-point data.

Double is a double-precision floating-point data.

2. The index range is different.

The index range of the float is -127 128.

The exponential range of double is -1023 10243, and the expression index is different.

The expression of float is 1 bit (sign bit) + 8 bits (exponential bit) + 23 bits (mantissa bit).

The expression of double is 1 bit (sign bit) + 11 bits (exponential bit) + 52 bits (mantissa bit).

4. The memory space occupied is different.

float occupies 4 bytes (32-bit) of memory space, and its values range as:

double occupies 8 bytes (64-bit) of memory space and its numeric range is.

5. The number of significant digits is different.

Float can only provide seven significant digits.

Double is available with 16 significant digits.

The differences between float and double are: different variable types, different exponential ranges, different exponential bits of expressions, different memory space, and different number of significant digits. The float data type is used to store single-precision floating-point numbers or double-precision floating-point numbers, while double-precision floating-point types use 64-bit to store a floating-point number.

1. Introduction to the meaning of float and double.

float is a single-precision floating-point type that is used to store single-precision floating-point or double-precision floating-point numbers. Floating-point numbers use the IEEE format. A single-precision value of the floating-point type has 4 bytes and includes a sign bit, an 8-bit binary exponent, and a 23-bit mantissa number.

Due to the mantissa of the mantissa number. The high order bit is always 1, so it is not stored in numeric form. This representation provides a range of float types approximately between .

Double, on the other hand, is a type of data used by computers, and compared to float, double uses 64 bits to store a floating-point number. It can represent 15 or 16 significant digits in the decimal system, with negative values ranging from to and positive values ranging from to .

2. The difference between float and double1. The variable type is different.

float belongs to single-precision floating-point data, and double belongs to double-precision floating-point data.

2. The index range is different.

The index range of the float is -127 128, and the index range of the double is -1023 1024.

3. The exponential digits of the expression are different.

The expression of float is 1 bit (sign bit) + 8 bits (exponential bit) + 23 bits (mantissa bit).The expression of double is 1 bit (sign bit) + 11 bits (exponential bit) + 52 bits (mantissa bit).

4. The memory space occupied is different.

float occupies 4 bytes (32-bit) of memory space, and its values range as: double occupies 8 bytes (64-bit) of memory space and its numeric range is.

5. The number of significant digits is different.

Float can only provide seven significant digits, and double can provide 16 significant digits.