If-Elseネストは冗長ですか？

Question

現在、私は地元の大学でC++コースを受講しており、デバッグの割り当てを受けています。この割り当ての指示では、このコードで本当に間違っているのは、82〜89行目のif-else-ifステートメントの条件が重複しているということですが、別の方法ではそれらの条件が同じでなくても同じ結果が得られます...ヒントなどがあれば幸いです！

#include <iostream> 
#include <conio.h> 
#include <iomanip> 

using namespace std; 

const int BASE_COST = 10; 
const int LOW_LIMIT = 20; 
const int MID_LIMIT = 40; 
const int HIGH_LIMIT = 60; 
const double LOW_CHECKS = .10; 
const double MIDLOW_CHECKS = .08; 
const double MIDHIGH_CHECKS = .06; 
const double HIGH_CHECKS = .04; 

int main() 
{ 
int numOfChecks; 
double multiplierValue; 
double totalFee; 

cout << fixed << showpoint; 
cout << setprecision(2); 
cout << "Please enter the number of checks you used this month: "; 
cin >> numOfChecks; 

if(numOfChecks < 0) 
{ 
    cout << "Number of checks can't be negative. Program ends.\n"; 
    exit(1); //terminate the program with error code 1 
} 

//the following line runs only if the program did not terminate, so start over if-else 
if(numOfChecks < LOW_LIMIT) 
    multiplierValue = LOW_CHECKS; 
else if(numOfChecks < MID_LIMIT) 
    multiplierValue = MIDLOW_CHECKS; 
else if(numOfChecks >= MID_LIMIT && numOfChecks < HIGH_LIMIT) 
    multiplierValue = MIDHIGH_CHECKS; 
else if (numOfChecks >= HIGH_LIMIT) 
    multiplierValue = HIGH_CHECKS; 

totalFee = BASE_COST + numOfChecks * multiplierValue; 

cout << "Your total for this month is $" << totalFee; 

_getch(); 
return 0; 
} 

Answer 1

この部分else if(numOfChecks >= MID_LIMIT && numOfChecks < HIGH_LIMIT)は冗長に見えます。あなたは範囲チェックの順序を保つ提供し、それを簡略化することができるちょうどelse if (numOfChecks < HIGH_LIMIT)、（ちょうど必要とされていない）、それを次のものと同じ曲全体は次のようになりますように：確かに、すべての

//the following line runs only if the program did not terminate, so start over if-else 
if (numOfChecks < LOW_LIMIT) 
    multiplierValue = LOW_CHECKS; 
else if (numOfChecks < MID_LIMIT) 
    multiplierValue = MIDLOW_CHECKS; 
else if (numOfChecks < HIGH_LIMIT) 
    multiplierValue = MIDHIGH_CHECKS; 
else 
    multiplierValue = HIGH_CHECKS; 

Answer 2

条件は冗長である：アルゴリズム:)

Live On Coliru

#include <iomanip> 
#include <map> 
#include <iostream> 

namespace { 
    using Threshold = unsigned; 
    using Rate  = double; 

    static Rate constexpr BASE_COST = 10.0; 

    std::map<Threshold, Rate, std::greater<> > const tariffs { 
     { 0, .10}, 
     {20, .08}, 
     {40, .06}, 
     {60, .04}, 
    }; 

    double fee(unsigned numOfChecks) { 
     auto rate = tariffs.lower_bound(numOfChecks); 
     return BASE_COST + rate->second * numOfChecks; 
    } 
} 

int main() { 
    unsigned numOfChecks; 
    std::cout << "Please enter the number of checks you used this month: "; 

    if (std::cin >> numOfChecks) { 
     std::cout 
      << "\nYour total for this month is $" 
      << std::fixed << std::showpoint << std::setprecision(2) << fee(numOfChecks) 
      << std::endl; 
    } else { 
     std::cout << "Invalid input\n"; 
     return 1; 
    } 
} 

プリントなどを使用します

Please enter the number of checks you used this month: 10 
Your total for this month is $11.00 

Please enter the number of checks you used this month: 20 
Your total for this month is $11.60 

Please enter the number of checks you used this month: 30 
Your total for this month is $12.40 

Please enter the number of checks you used this month: 40 
Your total for this month is $12.40 

Please enter the number of checks you used this month: 50 
Your total for this month is $13.00 

Please enter the number of checks you used this month: 60 
Your total for this month is $12.40 

Please enter the number of checks you used this month: 70 
Your total for this month is $12.80 

Please enter the number of checks you used this month: 80 
Your total for this month is $13.20 

Please enter the number of checks you used this month: 90 
Your total for this month is $13.60 

Please enter the number of checks you used this month: 100 
Your total for this month is $14.00