golang cast

Golang is a statically typed programming language, and type conversion operators need to be used when performing type conversion. There are two ways of type conversion in Golang: forced type conversion and implicit type conversion. In this article, we will focus on cast type conversion in golang.

1. The concept of forced type conversion

Forced type conversion is also called explicit type conversion, which means that the programmer forces the value of one type to be converted into the value of another type. Casting in Golang requires using parentheses to enclose the value that needs to be converted, and adding the type to be converted in front of the parentheses, that is, the cast operator. For example, to convert a float64 type value to an int type value:

var a float64 = 3.14
var b int = int(a)

In the above code, the variable a is forced to the int type, and the converted value is assigned to the variable b.

2. The syntax of forced type conversion

The syntax of forced type conversion is as follows:

Type(Value)

Type represents the type to be converted, and Value represents the value to be converted. You need to Value is placed in parentheses, for example:

var a float64 = 3.1415
var b int = int(a)

In the above code, we cast the float64 type a and assign the converted value to the int type variable b.

3. Notes on forced type conversion

1. Forced type conversion can only be performed between compatible types.

When performing forced type conversion, you must ensure that the type to be converted and the target type are compatible. For example, converting a float64 value to a string value is incompatible and will generate an error at compile time.

var a float64 = 3.1415
var b string = string(a) // 编译错误

2. Coercion may result in data loss or errors.

When performing forced type conversion, you need to pay attention to the range and overflow issues of data. For example, when converting a large integer type to a small integer type, high-order data may be lost, resulting in incorrect results.

var a int64 = 12345678910111213
var b int8 = int8(a) // 数据溢出，结果为 -115

In the above code, an integer type that is larger than the range of the int8 type is converted to the int8 type, resulting in data loss and incorrect results.

3. When calculating between different types, forced type conversion is required.

When performing calculations between different types, Golang will automatically perform type conversion and convert values ​​of different types according to certain rules. However, in some special cases, forced type conversion is required to ensure the correctness of the calculation.

For example, when adding a float64 type value to an int type variable, you need to cast the int type variable:

var a float64 = 3.1415
var b int = 2
var c float64 = a + float64(b)

In the above code, we convert the int type The variable b is forced to type conversion, and is added to the float64 type variable a, and the result is assigned to the c variable.

4. Summary

Forced type conversion is a type conversion method in Golang, which is used to convert a value of one type into a value of another type. When performing forced type conversion, you need to pay attention to compatibility issues as well as data range and overflow issues to ensure the correctness and stability of the program.

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