Simple way to obtain largest Number in an array or slice in golang

#webdev #beginners #go #arrays

🚀 Step-by-Step Guide to Find the Largest Number in an Array in Go

Finding the largest number in an array is a common task in programming. Let's walk through a simple yet effective approach to accomplish this in Go.

📝 Steps to Follow

1️⃣ Loop through Each Value

Iterate through each element of the array or slice.

2️⃣ Declare the Initial Largest Value

Initialize a variable largest with the first element of the array:
largest := array[0]

3️⃣ Compare the Current Largest Value with Other Numbers

Compare the current largest value with each element in the array.

4️⃣ Update the Largest Value

Whenever you find a number greater than the current largest value, update largest to this new number.

5️⃣ Return the Largest Value

After completing the loop, return the largest number.

func findLargestNumber(nums []int) int {
    if len(nums) == 0 {
        return 0 // handle empty slice case
    }
    largest := nums[0] // Step 2
    for i := 1; i < len(nums); i++ { // Step 1
        if nums[i] > largest { // Step 3
            largest = nums[i] // Step 4
        }
    }
    return largest // Step 5
}

Testing the function

func TestFindLargestNumber(t *testing.T) {
    tests := []struct {
        name     string
        numbers  []int
        expected int
    }{
        {
            name:     "Mixed positive numbers",
            numbers:  []int{45, 22, 68, 90, 12},
            expected: 90,
        },
        {
            name:     "All negative numbers",
            numbers:  []int{-5, -23, -1, -55},
            expected: -1,
        },
        {
            name:     "All zeros",
            numbers:  []int{0, 0, 0, 0, 0},
            expected: 0,
        },
    }

    for _, tt := range tests {
        t.Run(tt.name, func(t *testing.T) {
            got := findLargestNumber(tt.numbers)
            if got != tt.expected {
                t.Errorf("findLargestNumber(%v) = %v, want %v", tt.numbers, got, tt.expected)
            }
        })
    }
}

Main Function

func main() {
    arr := []int{45, 22, 68, 90, 12}
    fmt.Println(findLargestNumber(arr)) // Output: 90
}

Thanks for reading.
Kindly like and share other methods you know of in the comments below.

Top comments (7)

Christophe Colombier • Jun 13

Well, you could also use max introduced in Go 1.21

tip.golang.org/ref/spec#Min_and_max

Toluwase Thomas • Jun 13

thanks for sharing @ccoveille .
I looked it up and it seems that the difference is that max and min functions do not accept array or slice data structures directly. Instead, they accept individual values as arguments.

As shown below