add: slice adv. ops. exercises

16-slices/exercises/26-print-daily-requests/solution/main.go

@@ -0,0 +1,81 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import (
+	"fmt"
+	"strings"
+)
+
+func main() {
+	//
+	// DAILY REQUESTS DATA
+	//
+	reqs := []int{
+		500, 600, 250,
+		200, 400, 50,
+		900, 800, 600,
+		750, 250, 100,
+		100, 150,
+	}
+
+	//
+	// There are 3 requests per day
+	//
+	const N = 3
+
+	//
+	// Allocate the slice efficiently with the exact size needed
+	//
+	l := len(reqs)
+	size := l / N
+	if l%N != 0 {
+		size++
+	}
+	daily := make([][]int, 0, size)
+
+	//
+	// Group the `reqs` per day into a slice named: `daily`
+	//
+	for N < len(reqs) {
+		daily = append(daily, reqs[:N]) // add the current batch of nums to the `groups`
+		reqs = reqs[N:]                 // move the slice pointer for the next batch
+	}
+
+	//
+	// Add the residual elements to the group (len(reqs) % N)
+	//
+	daily = append(daily, reqs)
+
+	//
+	// Print the header:
+	//
+	fmt.Printf("%-10s%-10s\n", "Day", "Requests")
+	fmt.Println(strings.Repeat("=", 20))
+
+	//
+	// Print the data per day along with the totals:
+	//
+	var grand int
+
+	for i, d := range daily {
+		var sum int
+
+		for _, q := range d {
+			sum += q
+			fmt.Printf("%-10d%-10d\n", i+1, q)
+		}
+
+		fmt.Println(strings.Repeat("-", 20))
+		fmt.Printf("%10s%-10d\n\n", "", sum)
+
+		grand += sum
+	}
+
+	fmt.Printf("%10s%-10d\n", "", grand)
+}