Lab 2_Shell Script_Ver 2

#!/bin/sh

# @author LinChuWen
# course: Operating Systems Lab
# First Version: 2016.09.23
# Last Version:  2016.09.26

min=0
max=100
start=$min
end=$max

SetTarget(){
    printf "set a target: "
        read target; ans=$target
    Check;
}

Check(){
    if [ $ans -le $min ]; then
        echo "WRONG INPUT! your target must greater then $min"
        SetTarget;
    elif [ $ans -ge $max ]; then
        echo "WRONG INPUT! your target must less then $max"
        SetTarget;
    fi
}

Hello(){ echo "Welcome to the summoner's rift!"; }
Hello;

if [ $1 ]; then
    ans=$1; Check;
else SetTarget; fi

while [ $ans -lt $max ]; do
    printf "Guess a number between $start and $end: "
    read input

    if [ $input -gt $max ] || [ $input -lt $min ]; then
        echo "WRONG INPUT! range: $min ~ $max"
    elif [ $input -gt $ans ]; then
        if [ $input -lt $end ]; then
            end=$input; fi
    elif [ $input -lt $ans ]; then
        if [ $input -gt $start ]; then
            start=$input; fi
    else
        echo "BINGO! the answer is $ans !"
        break
    fi
done