This is Calculator Program, How to code for unknown number of inputs?

Question

This program is to do different calculations.right now it is only doing the basic operations for two numbers given in main, I'm trying to upgrade it to calculate for more than 2 numbers and more like for unknown number of number given in input.

package main

import (
    "fmt"
)

func add (n int , m int) int {
     sum := n + m
     return sum
}
func sub (n int , m int) int {
     diff := n - m
     return diff
}
func mul (n float32 , m float32) float32 {
     pro := n * m
     return pro
}

func div (n float32 , m float32) float32 {
     quo := n / m
     return quo
}

func main() {
    fmt.Println(add(4,6))
    fmt.Println(sub(4,6))
    fmt.Println(mul(4,6))
    fmt.Println(div(6,4))
}

Possible duplicate of [How do a simple calculator in Android? How to do it using Buttons and single edit text?](http://stackoverflow.com/questions/10280263/how-do-a-simple-calculator-in-android-how-to-do-it-using-buttons-and-single-edi) — Akshay Bhat 'AB', Jan 02 '17 at 05:34
Possible duplicate of [Calculator Problems - Android Programming](http://stackoverflow.com/questions/9435041/calculator-problems-android-programming) — Senjuti Mahapatra, Jan 02 '17 at 05:56
@SenjutiMahapatra @Akshay the question is not about how to write a calculator .It is about how to accept arbitary number of arguements in `go` functions — Sarath Sadasivan Pillai, Jan 02 '17 at 06:48

score 2 · Accepted Answer · answered Jan 02 '17 at 05:57

You may use ... to accept arbitery number of arguements, Here is how your program will be then

package main

import (
    "fmt"
)

func add(m ...int) int {
    sum := 0
    for _, i := range m {
        sum += i
    }
    return sum
}
func sub(m ...int) int {
    sub := m[0]
    for _, i := range m[1:] {
        sub -= i
    }
    return sub
}
func mul(m ...float32) float32 {
    c := float32(1)
    for _, i := range m {
        c *= i
    }
    return c
}
func div(m ...float32) float32 {
    quo := m[0]
    for _, i := range m[1:] {
        quo /= i
    }
    return quo
}

func main() {
    fmt.Println(add(4, 6))
    fmt.Println(sub(4, 6))
    fmt.Println(mul(4, 6))
    fmt.Println(div(6, 4))
}

Here is go play link : https://play.golang.org/p/dWrMa-GdGj

The 'go run filename.go' command compiles and runs the program, but I unable to find a command that just compiles the code and gives an executable file(.exe). Do you know how to do that? @Sarathsp — codinggirl, Jan 03 '17 at 02:39

score 0 · Answer 2 · answered Jan 02 '17 at 06:01

Your question isn't too clear, so I'm going to make some assumptions. I'm assuming you want something that can do add(1, 2, 3) that will return 1 + 2 + 3.

There are two ways of doing this, either using slices, or using the ...T argument type. (Refer to the Go specifications).

An implementation that makes use of slices will accept a slice of numbers, and then use iterative methods to perform actions on the slice. For example for an add function:

func add(numbers []int) int {
    sum := 0
    for _, number := range numbers {
        sum += number
    }
    return sum
}

You can then call it like add([]int{1, 2, 3}) which will return the result of 1 + 2 + 3.

Using the ...T argument type is almost the same, as it basically turns multiple arguments into a slice.

func add(numbers ...int) int {
    sum := 0
    for _, number := range numbers {
        sum += number
    }
    return sum
}

Except calling it becomes different. Either: add(1, 2, 3) or if you would still like to use a slice, add([]int{1, 2, 3}...).

You should be able to apply these concepts to your other operations.

This is Calculator Program, How to code for unknown number of inputs?

2 Answers2