86 lines
1.5 KiB
Go
86 lines
1.5 KiB
Go
package main
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import (
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"bufio"
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"fmt"
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"os"
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"strconv"
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"strings"
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)
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var stack []float64
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func pop() float64 {
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var x float64
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if len(stack) > 0 {
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x, stack = stack[len(stack)-1], stack[:len(stack)-1]
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}
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return x
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}
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func push(v float64) {
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stack = append(stack, v)
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}
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func addOp(v1, v2 float64) float64 {
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fmt.Printf("%f + %f = %f\n", v1, v2, (v1 + v2))
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return v1 + v2
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}
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func subtractOp(v1, v2 float64) float64 {
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fmt.Printf("%f - %f = %f\n", v1, v2, (v1 - v2))
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return v1 - v2
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}
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func multiplyOp(v1, v2 float64) float64 {
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fmt.Printf("%f * %f = %f\n", v1, v2, (v1 * v2))
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return v1 * v2
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}
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func divideOp(v1, v2 float64) float64 {
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fmt.Printf("%f / %f = %f\n", v1, v2, (v1 / v2))
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return v1 / v2
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}
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func main() {
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fmt.Println("stack calculator")
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var in string
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reader := bufio.NewReader(os.Stdin)
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for {
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fmt.Print(stack)
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fmt.Print(" > ")
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in, _ = reader.ReadString('\n')
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in = strings.TrimSpace(in)
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switch in {
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case ".":
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break
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case "+":
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doStackOperation(addOp)
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case "-":
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doStackOperation(subtractOp)
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case "*":
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doStackOperation(multiplyOp)
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case "/":
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doStackOperation(divideOp)
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default:
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val, err := strconv.ParseFloat(in, 64)
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if err != nil {
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fmt.Println(err.Error())
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fmt.Println("Valid inputs: +, -, /, *, <number>")
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fmt.Println("'.' by itself to quit")
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} else {
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push(val)
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}
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}
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if in == "." {
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break
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}
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}
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}
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func doStackOperation(op func(float64, float64) float64) {
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if len(stack) < 2 {
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fmt.Println("Not enough on stack to add")
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return
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}
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v1, v2 := pop(), pop()
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push(op(v1, v2))
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}
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