Add and subtract

Write the add and subtract functions.

Addition and subtraction

The first two operations are the simplest; each takes two float64 values and returns a float64. Parameters of the same type can be shortened to a, b float64:

func topla(a, b float64) float64 { return a + b }
func cikar(a, b float64) float64 { return a - b }

fmt.Println(topla(10, 4), cikar(10, 4))  // 14 6

Trying the functions

Trying each function with a few inputs right after writing it catches mistakes early. Try edge cases too: negative numbers, zero, decimals.

fmt.Println(topla(-2, 2))     // 0
fmt.Println(cikar(0.5, 0.25)) // 0.25

Later these checks turn into real test functions.

Exercise Two operations

Write the topla and cikar functions. Print the results of topla(10, 4) and cikar(10, 4) with one fmt.Println.

Show example solution

package main

import "fmt"

func topla(a, b float64) float64 { return a + b }
func cikar(a, b float64) float64 { return a - b }

func main() {
    fmt.Println(topla(10, 4), cikar(10, 4))
}

Test yourself

What does <code>cikar(4, 10)</code> return?
- -6
- 6
- 14
- An error
Show answer

-6 — Order matters: a - b = 4 - 10 = -6.

Subtraction

func cikar(a, b float64) float64 {
    return a ____ b
}

Show answer

func cikar(a, b float64) float64 {
    return a - b
}

Call and result

topla(10, 4)

14
cikar(10, 4)

6
cikar(4, 10)

-6
topla(-2, 2)

0

Next lesson: Multiply and divide

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