程序询问用户要进入哪个部门。进入该部门，然后询问用户希望在该部门内做什么。在用户想要做的任何事情的末尾，while循环询问"；下一步是什么&"；。如果用户输入"；0"；他们又回到了"；他们想输入哪个部门，用户输入相应部门的索引，但循环不会返回到用户选择的哪个部门。
简而言之：外部while循环执行，并使用内部while循环进入switch语句，但当用户返回外部while环时，该循环不会重新进入用户指定的部门。
// MAIN PROPGRAM
#include "client.h" // include appropriate .h files
#include "salesrep.h"
#include "product.h"
#include "sales.h"
#include <iostream> // include appropriate libraries
#include <fstream>
#include <cstdlib>
#include <string>
#include <vector>
#include <algorithm>
#include <iomanip>
using namespace std; // standard namespace
int main() {
Client alpha; // client class object
SalesRep beta; // sales rep class object
Product gamma; // product class object
Sales delta; // sales class object
int index; // index to traverse main menu
int subIndex; // index to traverse sub menu
cout << "Welcome to Wedling Central; we are happy you are here!" << endl; // greeting
cout << "Please select which department you would like to enter:" << endl; // orientation
cout << "Clients (Enter: 1)" << endl; // directories
cout << "Sales reps (Enter: 2)" << endl;
cout << "Products (Enter: 3)" << endl;
cout << "Sales (Enter: 4)" << endl;
cout << "Quit (Enter: 0)" << endl; // option to exit
cin >> index; // user input index for main menu
cin.ignore(); // ignore cin after index input
while (index != 0) { // while user does not wish to exit program
switch(index) {
case 1: // client department
while (subIndex != 0){ // while user does not wish to return to main menu
cout << "What would you like to do?" << endl; // prompt
cout << "Modify client (Enter: 1)" << endl; // options
cout << "Add new client (Enter: 2)" << endl;
cout << "Get a client's info (Enter: 3)" << endl;
cout << "View clients (Enter: 4)" << endl;
cout << "Go back to main menu (Enter: 0)" << endl; // return to main menu
cin >> subIndex; // user input for sub menu
cin.ignore(); // ignore cin after sub index input
switch(subIndex) { // options within department
case 1:
alpha.SetModifyClient(); // update a client
break; // return to sub menu
case 2:
alpha.SetNewClient(); // add new client
break; // return to sub menu
case 3:
alpha.GetSpecificClientInfo(); // view specific client's information
break; // return to sub menu
case 4:
alpha.GetAllClients(); // view all clients
break; // return to sub menu
}
}
break; // return to main menu
case 2:
while (subIndex != 0){ // while user does not wish to return to main menu
cout << "What would you like to do?" << endl; // prompt
cout << "Modify sales rep (Enter: 1)" << endl; // options
cout << "Add new sales rep (Enter: 2)" << endl;
cout << "Get a sales rep's info (Enter: 3)" << endl;
cout << "View sales reps (Enter: 4)" << endl;
cout << "View a sales rep's bonus (Enter: 5)" << endl;
cout << "Go back to main menu (Enter: 0)" << endl;
cin >> subIndex; // user input for sub menu
cin.ignore(); // ignore cin after sub index input
switch(subIndex) { // options within department
case 1:
beta.SetModifySalesRep(); // update a sales rep
break; // return to sub menu
case 2:
beta.SetNewSalesRep(); // add new sales rep
break; // return to sub menu
case 3:
beta.GetSpecificSalesRepInfo(); // view specific sales rep's information
break; // return to sub menu
case 4:
beta.GetAllSalesReps(); // view all sales reps
break; // return to sub menu
case 5:
beta.SalesRepBonus(); // view a sales rep's bonus
break; // return to sub menu
}
}
break; // return to main menu
case 3:
while (subIndex != 0) // while user does not wish to return to main menu
{
cout << "What would you like to do?" << endl; // prompt
cout << "Modify product (Enter: 1)" << endl; // options
cout << "Add new product (Enter: 2)" << endl;
cout << "Get a product's info (Enter: 3)" << endl;
cout << "View products (Enter: 4)" << endl;
cout << "View product sales (Enter: 5)" << endl;
cout << "Go back to main menu (Enter: 0)" << endl;
cin >> subIndex; // user input for sub menu
cin.ignore(); // ignore cin after sub index input
switch (subIndex)
{
case 1:
gamma.SetUpdateProduct(); // update product's information
break; // return to sub menu
case 2:
gamma.SetNewProduct(); // add new product
break; // return to sub menu
case 3:
gamma.GetSpecificProductInfo(); // view specific product's informatioin
break; // return to sub menu
case 4:
gamma.GetAllProduct(); // view all products
break; // return to sub menu
case 5:
gamma.MonthlySalesReport(); // view monthly sales report
break; // return to sub menu
}
}
break; // return to main menu
case 4:
while (subIndex != 0) // while user does not return to main menu
{
cout << "What would you like to do?" << endl; // prompt
cout << "Purchase a product (Enter: 1)" << endl; // options
cout << "View sales for the year (Enter: 2)" << endl;
cout << "View sales for a specific client (Enter: 3)" << endl;
cout << "Update client's sale (Enter: 4)" << endl;
cout << "Go back to main menu (Enter: 0)" << endl;
cin >> subIndex; // user input for sub menu
cin.ignore(); // ignore cin after sub index input
switch (subIndex)
{
case 1:
delta.PurchaseProduct(); // purchase a product
break; // return to sub menu
case 2:
delta.ViewAllSales(); // view sales
break; // return to sub menu
case 3:
delta.ViewClientSales(); // view specific client sales
break; // return to sub menu
case 4:
delta.UpdateClientSales(); // update client sales
break; // return to sub menu
}
}
break; // return to main menu
}
cout << "What is next?" << endl; // main menu return greeting
cout << "Please select which department you would like to enter:" << endl; // department orientation
cout << "Clients (Enter: 1)" << endl; // options
cout << "Sales reps (Enter: 2)" << endl;
cout << "Products (Enter: 3)" << endl;
cout << "Sales (Enter: 4)" << endl;
cout << "Quit (Enter: 0)" << endl; // exit index
cin >> index; // user input
cin.ignore(); // ignore cin after index input
}
cout << "Have a good day - thanks for stopping by Welding Central!" << endl; // farewell prompt
return 0; // end main
}
任何帮助都将不胜感激！
清除外循环中的子索引。可能发生的情况是，您得到一个索引1，并执行第一个switch语句。然后获取子索引一段时间，直到它们达到0，然后返回到外循环。这次选2。
但是子索引中已经有一个0，所以while循环立即退出。
如果你能更好地利用函数，这个代码会安全很多。每个内部循环都可以是一个单独的函数。这将消除下一次从一个切换条件漂移到下一个切换状态的变量。而且代码会更易读。