我正在为学校项目制作杂货店界面。首先有一个菜单询问用户是否要 S 购物或 Q 退出，如果他们选择 S，则会弹出一个显示产品的菜单，其中包含每磅的价格。然后用户可以通过输入数字 1-来选择产品7 然后选择他们想要多少磅该产品。我的问题是，在此之后我应该要求用户做出选择，选择可以是另一个产品，因此可以是 1-7 之间的数字，或者他们可以从新菜单中输入选项，即 T- 交易完成或 X- 取消交易。我设置代码的方式是，当要求用户进行其他选择时，我只能接受整数。我只编码了大约一个月，所以任何指导都会有很大帮助。
#include <iostream>
#include <iomanip>
#include <string>
#include <ctime>
#include <cctype>
#include <cstdlib>
#include <fstream>
#include <cmath>
using namespace std;
struct Transaction
{
string item;
float price;
//derived variables
float subTotal;
float totalSales;
};
// Decleration of prototype
void projectStart();
void projectEnd();
int getIntegerData(string);
float getFloatData(string);
char getCharData(string);
string getStringData(string);
void mainMenu();
void loadFile(int&, Transaction []);
void transactionShopping(int, Transaction[]);
void subMenu();
void performCalculation(int, Transaction[]);
int main()
{
// Displays start of project
projectStart();
cout << fixed <<setprecision(2);
//declared variables
Transaction myPurchase[25];
int itemSize;
itemSize = 0;
loadFile(itemSize, myPurchase);
transactionShopping(itemSize, myPurchase);
performCalculation(itemSize, myPurchase);
// Displays end of project
projectEnd();
return 0;
}// end of main
void performCalculation(int itemSize, Transaction myPurchase[])
{
float salesTax = .0825;
float subTotal = 0;
for (int ctr = 0; ctr < itemSize; ctr++)
{
subTotal = subTotal + myPurchase[ctr].subTotal;
}
}
void transactionShopping(int itemSize, Transaction myPurchase[])
{ // start of transactionShopping(int itemSize, Transaction myPurchase[])
//declared variables
string dashes(40, '-');
char selection;
int itemSelection;
float itemWeight;
float cost;
mainMenu();
selection = getCharData("\tMake your selection: ");
while(true)
{ // start of while(true)
if (selection == 'X')
{
cout << "!!! Transaction Cancelled" << endl;
break;
}
else
{ if (selection == 'S')
{//start of if (selection == 'S')
cout << dashes << endl;
cout << "\tHernandez Grocery Store" << endl;
cout << dashes << endl;
cout << "Shopping" << endl;
for (int ctr = 0; ctr < itemSize; ctr++ )
{ //start of for loop
cout << ctr + 1 << " "<< myPurchase[ctr].item << " " << myPurchase[ctr].price << endl;
} //end of for loop
subMenu();
itemSelection = getIntegerData("\tMake your selection: ");
if (itemSelection >= 1 && itemSelection <= itemSize)
{ //start of if loop
itemWeight = getFloatData("\tEnter pounds of " + myPurchase[itemSelection -1].item + ": ");
if (itemWeight > 0)
{ //start of itemweight loop
cost = itemWeight * myPurchase[itemSelection -1].price;
cout << "\tCost: " << itemWeight << " lbs" << " of " << myPurchase[itemSelection -1].item << ": $" << cost << endl;
} // end of itemweight loop
else
{ //start of else
cout << "ERROR Message. Enter a valid weight" << endl;
} //end of else
}
else if (selection == 'T')
{
cout << "Grocery List" << endl;
cout << "myPurchase[itemSelection -1].item" << endl;
}
}
}
}
} // end of transactionShopping(int itemSize, Transaction myPurchase[])
// menu function
void subMenu()
{ //start of subMenu
string dashes(40, '-');
cout << dashes << endl;
cout << "T Complete Transaction" << endl;
cout << "X Cancel Transaction" << endl;
} //end of subMenu
void mainMenu()
{ //start of mainMenu
string dashes(40, '-');
cout << dashes << endl;
cout << "Hernandez Grocery store" << endl;
cout << dashes << endl;
cout << "Main Menu" << endl;
cout << "\tS Shop" << endl;
cout << "\tQ Quit" << endl;
cout << dashes << endl;
} //end of mainMenu
//function will load the file
void loadFile(int & itemSize, Transaction myPurchase[])
{ //start of void loadFile(int & itemSize, Transaction myPurchase[])
ifstream menuFile("menu.txt");
string item;
float price;
itemSize = 0;
if (menuFile)
{ //if (menuFile)
while (menuFile >> item >> price)
{ // start of while (menuFile >> item >> price)
myPurchase[itemSize].item = item;
myPurchase[itemSize].price = price;
itemSize = itemSize + 1;
if (itemSize == 25)
{
break;
}
} //while while (menuFile >> item >> price)
menuFile.close();
}// if (menuFile)
else
{
cout << "File does not exist" << endl;
}
} //end of void loadFile(int & itemSize, Transaction myPurchase[])
char getCharData(string prompt)
{ //start of getCharData
char value;
while (true)
{ //start of while(true)
cout << prompt;
cin >> value;
cin.clear(); //clears the cin
cin.ignore(120, '\n'); //clears up to 120 characters or until enter button is hit
value = toupper(value);
if (value == 'S' || value == 'Q' || value == 'T' || value =='X')
{
return value;
}
cout << "\t\tError Message Invalid Selection" << endl;
}
} //end of getCharData
// This function will get a float value from the user
float getFloatData(string prompt)
{
float value;
while (true)
{
cout << prompt;
while (!(cin >> value))
{
cout << "\t\tError Message. Non numeric is entered" << endl;
cin.clear();
cin.ignore(120, '\n');
cout << prompt;
}
if (value >= 1 && value <= 10)
{
return value;
}
cout << "\t\tError Message. ONLY integers between 1 and 10" << endl;
}
}
// This function will get an integer value from the user
int getIntegerData(string prompt)
{
int value;
while (true)
{
cout << prompt;
while (!(cin >> value))
{
cout << "\t\t\tError Message. Non numeric is entered" << endl;
cin.clear(); // clear error buffer
cin.ignore(120, '\n'); // c;lear upto 120 chars or it reaches an enter
cout << prompt;
} // while (!(cin >> value))
if (value >= 1 && value <= 7)
{
return value;
}
cout << "Enter from provided options 1-7" << endl;
} // end of while (true)
} // end of int getIntegerData()
// This function will return a string data entered by users
string getStringData(string prompt)
{
string value;
cout << prompt;
getline(cin, value, '\n'); // accepts spaces in the entry
return value;
} // end of int getStringData(string prompt)
// The function will display the start of the project
void projectStart()
{
cout << "-----------------------------" << endl;
cout << "Project " << endl;
cout << "Objectives" << endl;
cout << "\tUser can nagivate our product list and pick the product and amount they would like" << endl;
cout << "\tThe user will receive a total price at the end or exit if they choose to cancel " << endl;
cout << "-----------------------------" << endl;
} // end of projectStart()
// The function will display the end of the project
void projectEnd()
{
cout << "-----------------------------" << endl;
cout << "End of Project" << endl;
cout << "-----------------------------" << endl;
} // end of projectEnd()```
I tried replacing my itemSelection = getIntegerData("\tMake your selection: "); with getCharData but not sure if this can even work since i would have to change my getchardata function to check for integers would entering them as '1' work?
您可以读入一个字符，即。
char input; std::cin >> inputinput >= '0' && input <= '9'input - '0'