Go Integer Data Type

In Go, integer data types are used to represent numbers without decimal points, like 150, -72, or 100000.

Integer data types are classified into two main categories:

1. Signed Integers
   These integers can store both positive and negative values.
2. Unsigned Integers
   These integers are restricted to storing only non-negative values.

Note: If you don’t specify an integer type explicitly, the default type is int.

Signed Integers

Signed integers are declared using one of the int keywords and can hold values that are either positive or negative.

Example: Declaring Signed Integers

package main

import ("fmt")

func main() {
    var engineCapacity int = 1200   // Signed integer (positive)
    var fuelEfficiency int = -20   // Signed integer (negative)

    fmt.Printf("Type: %T, value: %v\n", engineCapacity, engineCapacity)
    fmt.Printf("Type: %T, value: %v\n", fuelEfficiency, fuelEfficiency)
}

Output:

Type: int, value: 1200  
Type: int, value: -20  

Types of Signed Integers in Go

Unsigned Integers

Unsigned integers are declared using one of the uint keywords and can store only non-negative values.

Example: Declaring Unsigned Integers

package main

import ("fmt")

func main() {
    var bikePrice uint = 1500000   // Unsigned integer (positive only)
    var insuranceFee uint = 25000 // Unsigned integer (positive only)

    fmt.Printf("Type: %T, value: %v\n", bikePrice, bikePrice)
    fmt.Printf("Type: %T, value: %v\n", insuranceFee, insuranceFee)
}

Output:

Type: uint, value: 1500000  
Type: uint, value: 25000  

Types of Unsigned Integers in Go

Choosing the Right Integer Type

When selecting an integer type, consider the range of values the variable will store.

Example of Incorrect Type Assignment

This example demonstrates an error caused by assigning a value beyond the range of int8 (valid range is -128 to 127):

package main

import ("fmt")

func main() {
    var maxSpeed int8 = 300    // Out of range for int8
    fmt.Printf("Type: %T, value: %v\n", maxSpeed, maxSpeed)
}

Result:

./prog.go:5:7: constant 300 overflows int8