Data Types & Strict Casting

🐹 Go Language Lesson 3 Beginner

Go enforces an extremely strict type system. Unlike languages that automatically cast numeric types, Go requires explicit casting for every single conversion.

1 Go Primitives & Formatting Specifiers

Go primitives include boolean, numeric types (integers `int8`, `int32`, `int64`, unsigned `uint`, floats `float32`, `float64`), and string types.

Strict Type Conversions: Go does not perform implicit type casting. Even converting an `int32` to an `int64` requires an explicit type cast: `var longVal int64 = int64(int32Val)`. If you try to compile code that performs implicit conversions (like `int + float`), compilation will fail.

2 Cast Operations Code

Let's run a program demonstrating casting and type formatting check specifiers:

Go — Casting and Type Specifiers ▶ Run Code

package main

import "fmt"

func main() {
    intVal := 42
    floatVal := 5.5

    // Explicit casting to double float64 before math operation
    result := float64(intVal) * floatVal
    fmt.Printf("Result value: %f\n", result)

    // Investigating type metadata (%T formats type string)
    fmt.Printf("Type of intVal: %T\n", intVal)
    fmt.Printf("Type of floatVal: %T\n", floatVal)
}

3 Code Challenge

Challenge: Write a program that defines an integer representing score items, and a float representing total possible items. Perform a division operation to calculate the percentage. Cast variables explicitly to avoid compilation errors and print the result.