Converting Between Numeric Types in Go: int, float, and more

Understanding Numeric Types in Go

Go is a statically typed language, and it provides several types of numerical types such as int, int8, int32, int64, uint, float32, float64, and others. Understanding how to convert between these types is crucial for performing calculations and optimizations in your programs.

Basic Conversion Between Numeric Types

Let’s begin with the basics of converting between integer types in Go.

package main

import "fmt"

func main() {
    var i int = 42
    var j int64 = int64(i) // Convert int to int64
    fmt.Println(j)
    
    var f float64 = float64(i) // Convert int to float64
    fmt.Println(f)
}

In the example above, Go requires explicit conversion between different numeric types. Simple casting using parentheses does not work in Go as it does in some other languages like C or C++.

Intermediate Conversion: Between Float and Integers

When converting from floating-point numbers to integers, Go automatically truncates the decimal portion. Let’s see this behavior:

package main

import "fmt"

func main() {
    var pi float64 = 3.14159265

    var intPi int = int(pi) // Truncate the value
    fmt.Println(intPi) // Outputs: 3

    var roundedFloat float64 = pi + 0.5
    var roundedInt int = int(roundedFloat) // Simple method to round
    fmt.Println(roundedInt) // Outputs: 4
}

In this snippet, converting a float to an int truncates the decimal. Often, adding 0.5 can help round the number correctly before converting, but beware of edge cases.