hennge.go

// challenge detail: https://thecodercat.com/notes/read/hennge.md

package main

import (
	"bufio"
	"errors"
	"fmt"
	"os"
	"strconv"
	"strings"
)

func main() {
	var result []int
	// this is the number of test case
	reader := bufio.NewReader(os.Stdin)
	num, err := reader.ReadString('\n')
	num = strings.Replace(num, "\n", "", -1)

	check(err)
	numberOfTest, err := strconv.Atoi(string(num))
	check(err)
	
	if numberOfTest < 1 || numberOfTest > 100 {
		check(errors.New("no! give me a number > 0 and <= 100"))
	}
	
	input(&result, numberOfTest, 1)
	fmt.Println(strings.Trim(strings.Replace(fmt.Sprint(result), " ", "\n", -1), "[]"))
}

func input(result *[]int, numberOfTest int, currentTest int) {
	if currentTest <= numberOfTest {
		// read the number of integer will be input in the next line
		squareSum := 0
		ss := inputTest()
		calculateSum(&squareSum, 0, ss)
		currentTest++
		*result = append(*result, squareSum)
		input(result, numberOfTest, currentTest)
	}
}

func inputTest() (ss []string) {
	reader := bufio.NewReader(os.Stdin)
	num, err := reader.ReadString('\n')
	check(err)
	num = strings.Replace(num, "\n", "", -1)
	count, err := strconv.Atoi(string(num))
	if count < 1 || count > 100 {
		check(errors.New("a number that >= 1 and <= 100 please"))
	}
	check(err)
	intStr, err := reader.ReadString('\n')
	intStr = strings.Replace(intStr, "\n", "", -1)
	check(err)

	ss = strings.Split(intStr, " ")

	if len(ss) != count {
		check(errors.New(fmt.Sprintf("no! give me %d numbers", count)))
	}
	return
}

func calculateSum(total *int, fromPos int, str []string) int {
	if fromPos < len(str) {
		number, err := strconv.Atoi(str[fromPos])
		check(err)
		if number > 100 || number < -100 {
			check(errors.New("number out of range"))
		}
		if number >= 0 {
			*total += number * number
		}
		fromPos++
		calculateSum(total, fromPos, str)
	}
	return *total
}

func check(e error) {
	if e != nil {
		panic(e)
	}
}