// a statement of the type:
// T(v)
// where T is a type and v is a value converts
// v to the type T

package main

import (
    "fmt"
    "math"
)

func main() {
    // x and y are of type int
    x, y := 3, 4
    
    // can't do this directly!
    // math.Sqrt expects a string
    // z := math.Sqrt(x * x + y * y)
    // you should cast the value first:

    z := math.Sqrt(float64(x * x + y * y))

    fmt.Println("Type: %T Value: %v", x, x)
    fmt.Println("Type: %T Value: %v", y, y)
    fmt.Println("Type: %T Value: %v", z, z)

}