just some practice with syntax, playing with go. This converts Farenheit<->Celsius.

tConv.go

//File tConv.go
//=================================================
//syntax:
// ./tConv -F 96
// Output: 96.00°F is equal to 35.56°C

//./tConv -C 35.5
// Output: 35.50°C is equal to 95.90°F
//=================================================

package main
 
import (
    "fmt"
    "flag"
    "strconv"
)

func FtoS(input_num float64) string {
    // to convert a float number to a string
    return strconv.FormatFloat(input_num, 'f', 2, 64)
}

type myTemp struct {
	Temp float64
	Unit string
}

const degree = "°"
const degF = "°F"
const degC = "°C"

func main() {   
    var isCtemp = flag.Bool("C", false, "Is Celsius temp to converting to Farenheit")
    var isFtemp = flag.Bool("F", true, "Is Farenheit temp to converting to Celsius")
    var args []string 
    var in myTemp
    var out myTemp    
    var err error  
    
    flag.Parse()
    args = flag.Args() 
    
    if len(args) == 1 {
		in.Temp, err = strconv.ParseFloat(args[0], 64)
		if err != nil {
			fmt.Println("temp wasn't the first entry after the flags, or was not a number")
			return 
		}
	}
        
    if *isCtemp == true {
		//°F = °C  x  9/5 + 32
		out.Temp = (in.Temp * (9.0/5.0)) + 32.0
		out.Unit = degF
		in.Unit = degC
	 } else if *isFtemp == true {
		//°C = (°F  -  32)  x  5/9 
		out.Temp = (in.Temp - 32.0) * (5.0/9.0)
		out.Unit = degC
		in.Unit = degF
	} else {
		fmt.Println("No input temp was specified (-F or -C flags)")
		return
	}
    
    fmt.Println(FtoS(in.Temp) + in.Unit + " is equal to " + FtoS(out.Temp) + out.Unit + "\n")
}