What is type int16 in Golang?

In the Go programming language, variables are containers marked by identifiers or names, which can hold different values in a program. These variables can hold all different data types, whether they are numbers, words, or any other type. To restrict the type of data stored inside these variables, we need to specify the data type of the variables.

int is one of the available numeric data types in Go used to store signed integers. int16 is a version of int that only stores signed numeric values composed of up to 16 bits; if you, for example, try to store a string value in it, or an integer beyond what can be made using 16 bits the program would return an error or result in an integer overflow.

Similar variants

The numeric data type of int has several other versions in addition to int16, which include:

  • int8
  • int32
  • int64
  • uint8
  • uint16
  • uint32
  • uint64

The data types starting from int store signed integers while those starting with uint contain unsigned integers, and the numeric value that follows each data type represents the number of bytes stored.

Range

A variable of type int16 can store integers ranging from -32768 til 32767

If an int16 variable is assigned a value beyond the range mentioned above, then an overflow error occurs, which basically means that the int16 variable cannot properly store the assigned number.

Overflow

The following code shows the positive limit of the values that an int16 variable can store and what happens if you try storing something larger than the stipulated range of values:

package main
import "fmt"
func main() {
// initializing with the maximum allowed positive number
var num int16 = 32767
// printing the value and data type
fmt.Printf("Value is: %d and type is: %T\n", num, num);
// making the value out of range by incrementing by 1
num = num+1
// printing out new value and type
fmt.Printf("Value is: %d and type is: %T\n", num, num);
}

As we can see from the outputs of the code above, when we stored the value 32767 in num and printed it, the value came out to be 32767. However, just incrementing it by 1 pushed it out of the allowed range, which resulted in the stored value being interpreted as -32768 when printed again. When this happens, we call it an overflow.

Examples

In the following example, we declare a variable num explicitly stating its data type to be int16. Later, we can use the Printf function to see that num is indeed stored as an int16 data type:

package main
import "fmt"
func main() {
var num int16
num = 200
fmt.Printf("Data type of %d is %T\n", num, num);
}

It is also possible to create const values of type int16 instead of variables. The only difference is that const values are just variables whose values can not be changed from what it was initialized to. We then check the stored data type again by printing it out using the Printf function.

const values must be declared and initialized in the same line.

package main
import "fmt"
func main() {
// declaring and initializing a const value with an integer
const c_num int16 = 200
// %T represents the type of the variable num
fmt.Printf("Data type of %d is %T\n", c_num, c_num);
}
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