程序卡在无限循环

Question

我试图让这个程序正常运行。它应该像上面描述的那样执行伪代码，但是当我执行程序并尝试打开一个新帐户时，如果我在客户名字段中放置了多个字符，程序就会进入无限循环，并且我已经知道如何解决这个问题。

#include "stdafx.h" 
#include <iostream> 
#include <string> 
#include <conio.h> 
#include <iomanip> 
using namespace std; 

int choice, account_number; 
long acc_entry; 
long acc_no = 112280; 
double balance, deposit, withdrawal; 
int interest = 1.67; 
string customer_name; 

void display_menu(); 
void get_choice(); 
void menu_selection(int selection); 
void open_account(); 
void make_withdrawal(); 
void make_deposit(); 
void add_interest(); 
void display_transaction(); 

void main() 
{ 
    get_choice(); 

} 

void display_menu() 
{ 
    system("CLS"); 
    cout << "\n\n\t\t\t\tACCOUNT MENU"; 
    cout << "\n\t\t\t\t============\n"; 
    cout << "\n\t\t\t\t1. Open Account"; 
    cout << "\n\t\t\t\t2. Make Withdrawal"; 
    cout << "\n\t\t\t\t3. Make Deposit"; 
    cout << "\n\t\t\t\t4. Add Interest"; 
    cout << "\n\n\t\t\t\t5. Exit"; 
} 

void open_account() 
{ 
    system("CLS"); 
    cout << "\n\n\t\t\t\tOPEN ACCOUNT"; 
    cout << "\n\t\t\t\t============\n\n"; 
    cout << "\tPlease enter your name\n\n\t"; 
    cin >> customer_name; 
    cout << "\n\n\tPlease enter initial despoit\n\n\t"; 
    cin >> deposit; 
    balance = balance + deposit; 
    account_number = acc_no + 1; 
    cout << "\n\n\tYour new account number\n\n\t" << setfill('0') << setw(8) << account_number; 
    get_choice(); 
} 

void make_withdrawal() 
{ 
    system("CLS"); 
    cout << "\n\n\t\t\t\tMAKE WITHDRAWAL"; 
    cout << "\n\t\t\t\t===============\n\n"; 
    cout << "\tPlease enter Account Number\n\n\t"; 
    cin >> acc_entry; 
    if (acc_entry == account_number) 
    { 
     cout << "\n\n\tPlease enter amount to withdraw\n\n\t"; 
     cin >> withdrawal; 
     if (withdrawal > balance) 
     { 
      cout << "\n\n\tYou are exceeding your limit"; 
      cin.ignore(); 
      cin.get(); 
     } 
     else 
     { 
      balance = balance - withdrawal; 
      cout << "\n\n\tYour new balance\n\n\t" << fixed << setprecision(2) << (char)156 << balance; 
      cin.ignore(); 
      cin.get(); 
     } 
    } 
    else 
    { 
     cout << "\n\n\tAccount number does not exist."; 
     cin.ignore(); 
     cin.get(); 
    } 
    get_choice(); 
} 

void make_deposit() 
{ 
    system("CLS"); 
    cout << "\n\n\t\t\t\tMAKE DEPOSIT"; 
    cout << "\n\t\t\t\t============\n\n"; 
    cout << "\tPlease enter Account Number\n\n\t"; 
    cin >> acc_entry; 
    if (acc_entry == account_number) 
    { 
     cout << "\n\n\tPlease enter amount to deposit\n\n\t"; 
     cin >> deposit; 
     balance = balance + deposit; 
     cout << "\n\n\tYour new balance\n\n\t" << fixed << setprecision(2) << (char)156 << balance; 
     cin.ignore(); 
     cin.get(); 
    } 
    else 
    { 
     cout << "\n\n\tAccount number does not exist."; 
     cin.ignore(); 
     cin.get(); 
    } 
    get_choice(); 
} 

void add_interest() 
{ 
    string yn; 
    system("CLS"); 
    cout << "\n\n\t\t\t\tADD INTEREST"; 
    cout << "\n\t\t\t\t============\n\n"; 
    cout << "\tPlease enter Account Number\n\n\t"; 
    cin >> acc_entry; 
    if (acc_entry == account_number) 
    { 
     cout << "\n\n\tDo you wish to add interest [Y/N]\n\n\t"; 
     getline(cin, yn); 
     if (yn == "Y" || yn == "y") 
     { 
      balance = balance * interest; 
      cout << "\n\n\tYour new balance\n\n\t" << fixed << setprecision(2) << (char)156 << balance; 
      cin.ignore(); 
      cin.get(); 
     } 
    } 
    else 
    { 
     cout << "\n\n\tAccount number does not exist."; 
     cin.ignore(); 
     cin.get(); 
    } 
    get_choice(); 
} 

void display_transaction() 
{ 
    system("CLS"); 

    cout << "\n\n\t\t\t\tCLOSED"; 
    cout << "\n\t\t\t\t======\n\n"; 
    if (account_number != 112280) 
    { 
     cout << "\tCustomer Name : - " << customer_name; 
     cout << "\n\n\tAccount Number : - " << setfill('0') << setw(8) << account_number; 
     cout << "\n\n\tBalance  : - " << fixed << setprecision(2) << (char)156 << balance << "\n\n"; 
    } 
    cin.get(); 
} 

void get_choice() 
{ 
    display_menu(); 
    do 
    { 

     cout << "\n\n\t\t\t\tEnter Number [1-5] : "; 
     cin >> choice; 
     menu_selection(choice); 
    } while 
     (choice << 1 || choice >> 5); 
     cin.ignore(); 

} 

void menu_selection(int a) 
{ 
    switch (a) 
    { 
    case 1: 
    { 
     open_account(); 
     break; 
    } 
    case 2: 
    { 
     make_deposit(); 
     break; 
    } 
    case 3: 
    { 
     make_withdrawal(); 
     break; 
    } 
    case 4: 
    { 
     add_interest(); 
     break; 
    } 
    case 5: 
    { 
     display_transaction(); 
     break; 
    } 
    default: 
     { 
     cout << "hello"; 
     } 
    } 
} 

Answer 1

void get_choice() 
{ 
    display_menu(); 
    do 
    { 

     cout << "\n\n\t\t\t\tEnter Number [1-5] : "; 
     cin >> choice; 
     menu_selection(choice); 
    } while 
     (choice < 1 || choice > 5); // <<and>> aren't for comparison 
     cin.ignore(); 

} 

Answer 2

在你get_choice功能，你有一个do-while环路与以下条件：

while (choice << 1 || choice >> 5); // this is going to run for a bit 

<<和>>不是比较符;相反，他们是bit shift operators。

因为您的选择可以向左或向右移动，它会进入无限循环。这是一个简单的修复，真的 - 将它们改为比较运算符！

至于客户名称，如果有空格或换行符，std::cin将停止阅读第一个。请务必使用std::getline从stdin读取字符串。与此

cin >> customer_name; 

：

在open_account，更换此

std::getline(cin, customer_name); 

而且，解决这一行：

int interest = 1.67; // This should be a double 

你不应该使用全局真的，但这是一个完全不同的故事。