如果用户选择“是”，则执行while循环以重新启动程序，但操作不正确 我学习C++，我们还没有在C++中覆盖循环，但我觉得有必要进入新的领域，所以我从头开始做了一个程序，有点像杂货店，在程序的最后，它询问用户是否想多购物，如果他/她键入Y，那么它重新启动，如果他/她键入N，那么它退出。当我在节目结束时输入Y时，它会一直问“你想继续购物吗？是[Y]还是否[N]”。怎么了 #include <iostream> #include <sstream> #include <string> using namespace std; char shoppingMenu() { char chrSelect = ' '; cout << "%%%%%%%%%%%%" << endl; cout << "% Shopping %" << endl; cout << "%%%%%%%%%%%%" << endl << endl; cout << "Prepared Foods:" << endl; cout << "A.) Lettuce" << endl; cout << "B.) Noodles" << endl; cout << "C.) Bottled Water" << endl; //shopSelection = cin.get(); cin >> chrSelect; return toupper(chrSelect); } double lettuce(int numWeight, double numQuant) { system("CLS"); cout << "%%%%%%%%%%%" << endl; cout << "% Lettuce %" << endl; cout << "%%%%%%%%%%%" << endl; cout << "Lbs: "; cin >> numWeight; cout << endl << "Quantity: "; cin >> numQuant; return numQuant * (numWeight * .75); } double noodles(double numQuant) { system("CLS"); cout << "%%%%%%%%%%%" << endl; cout << "% Noodles %" << endl; cout << "%%%%%%%%%%%" << endl << endl; cout << endl << "Number of 1/2lb packs: "; cin >> numQuant; return numQuant * 1.50; } double water(char chrSelection, int numQuant) { system("CLS"); cout << "%%%%%%%%%" << endl; cout << "% Water %" << endl; cout << "%%%%%%%%%" << endl << endl; cout << endl << "A.) 12pk;"; cout << endl << "B.) 24pk;" << endl; cout << "Please enter [A] or [B]" << endl; cin >> chrSelection; //cout << '\b' << endl; chrSelection = toupper(chrSelection); cout << "Quantity: "; cin >> numQuant; if (chrSelection == 'A') { return numQuant * 1.49; } else if (chrSelection == 'B') { return numQuant * 2.49; } } int main() { char selection = ' '; int numberLettuce = 0; double lettuceWeight = 0.0; int lettuceQuant = 0; double lettuceTotal = 0.0; int noodleQuant = 0; double noodleTotal = 0.0; char waterSelection = ' '; int waterQuant = 0; double waterTotal = 0.0; char keepShopping = ' '; cout << "#################" << endl; cout << "# Grocery Store #" << endl; cout << "#################" << endl << endl; do { cout << "How may i help you?" << endl; cout << "A.) Shopping Program" << endl; selection = cin.get(); selection = toupper(selection); system("CLS"); if (selection == 'A') { char shopSelection = shoppingMenu(); // Display Menu cout << "(Selection == " << selection << ")" << endl; if (shopSelection == 'A') { lettuceTotal = lettuce(lettuceWeight, lettuceQuant); } else if (shopSelection == 'B') { noodleTotal = noodles(noodleQuant); } else if (shopSelection == 'C') { waterTotal = water(waterSelection, waterQuant); } system("CLS"); cout.precision(2); cout << fixed; cout << " Lettuce total: $" << lettuceTotal << endl; cout << " Noodle total: $" << noodleTotal << endl; cout << " + Water total: $" << waterTotal << endl; cout << "----------------------------" << endl; cout << " = $" << (lettuceTotal + noodleTotal + waterTotal); } cout << endl << endl << "Do you want to continue shopping? Yes[Y] or No[N]" << endl; cin >> keepShopping; keepShopping = toupper(keepShopping); system("CLS"); } while (keepShopping == 'Y'); system("pause"); } #包括 #包括 #包括 使用名称空间std； char shoppingMenu（） { char chrSelect=''； 问题是 cin >> keepShopping;
其中，如果用户选择“是”，则执行while循环以重新启动程序，但操作不正确 我学习C++，我们还没有在C++中覆盖循环，但我觉得有必要进入新的领域，所以我从头开始做了一个程序，有点像杂货店，在程序的最后，它询问用户是否想多购物，如果他/她键入Y，那么它重新启动，如果他/她键入N，那么它退出。当我在节目结束时输入Y时，它会一直问“你想继续购物吗？是[Y]还是否[N]”。怎么了 #include <iostream> #include <sstream> #include <string> using namespace std; char shoppingMenu() { char chrSelect = ' '; cout << "%%%%%%%%%%%%" << endl; cout << "% Shopping %" << endl; cout << "%%%%%%%%%%%%" << endl << endl; cout << "Prepared Foods:" << endl; cout << "A.) Lettuce" << endl; cout << "B.) Noodles" << endl; cout << "C.) Bottled Water" << endl; //shopSelection = cin.get(); cin >> chrSelect; return toupper(chrSelect); } double lettuce(int numWeight, double numQuant) { system("CLS"); cout << "%%%%%%%%%%%" << endl; cout << "% Lettuce %" << endl; cout << "%%%%%%%%%%%" << endl; cout << "Lbs: "; cin >> numWeight; cout << endl << "Quantity: "; cin >> numQuant; return numQuant * (numWeight * .75); } double noodles(double numQuant) { system("CLS"); cout << "%%%%%%%%%%%" << endl; cout << "% Noodles %" << endl; cout << "%%%%%%%%%%%" << endl << endl; cout << endl << "Number of 1/2lb packs: "; cin >> numQuant; return numQuant * 1.50; } double water(char chrSelection, int numQuant) { system("CLS"); cout << "%%%%%%%%%" << endl; cout << "% Water %" << endl; cout << "%%%%%%%%%" << endl << endl; cout << endl << "A.) 12pk;"; cout << endl << "B.) 24pk;" << endl; cout << "Please enter [A] or [B]" << endl; cin >> chrSelection; //cout << '\b' << endl; chrSelection = toupper(chrSelection); cout << "Quantity: "; cin >> numQuant; if (chrSelection == 'A') { return numQuant * 1.49; } else if (chrSelection == 'B') { return numQuant * 2.49; } } int main() { char selection = ' '; int numberLettuce = 0; double lettuceWeight = 0.0; int lettuceQuant = 0; double lettuceTotal = 0.0; int noodleQuant = 0; double noodleTotal = 0.0; char waterSelection = ' '; int waterQuant = 0; double waterTotal = 0.0; char keepShopping = ' '; cout << "#################" << endl; cout << "# Grocery Store #" << endl; cout << "#################" << endl << endl; do { cout << "How may i help you?" << endl; cout << "A.) Shopping Program" << endl; selection = cin.get(); selection = toupper(selection); system("CLS"); if (selection == 'A') { char shopSelection = shoppingMenu(); // Display Menu cout << "(Selection == " << selection << ")" << endl; if (shopSelection == 'A') { lettuceTotal = lettuce(lettuceWeight, lettuceQuant); } else if (shopSelection == 'B') { noodleTotal = noodles(noodleQuant); } else if (shopSelection == 'C') { waterTotal = water(waterSelection, waterQuant); } system("CLS"); cout.precision(2); cout << fixed; cout << " Lettuce total: $" << lettuceTotal << endl; cout << " Noodle total: $" << noodleTotal << endl; cout << " + Water total: $" << waterTotal << endl; cout << "----------------------------" << endl; cout << " = $" << (lettuceTotal + noodleTotal + waterTotal); } cout << endl << endl << "Do you want to continue shopping? Yes[Y] or No[N]" << endl; cin >> keepShopping; keepShopping = toupper(keepShopping); system("CLS"); } while (keepShopping == 'Y'); system("pause"); } #包括 #包括 #包括 使用名称空间std； char shoppingMenu（） { char chrSelect=''； 问题是 cin >> keepShopping;,c++,C++,其中，keepShopping是一个char。当您键入YEnter时，您已经键入了两个字符。第一个字符进入keepShopping，您的程序正确地循环回到do循环的顶部。然后，selection=cin.get（）读取输入缓冲区中的下一个字符，即回车键，它不是A，因此它会下降到if块的末尾，询问您是否要再次继续购物 解决方案是避免使用cin，而是使用getline（） string str; getline(cin, str); keepShopping = str[0]; 这将消耗您键入的所
keepShoppingcharkeepShoppingdoselection=cin.get（）Aifcingetline（）string str;
getline(cin, str);
keepShopping = str[0];
cin>cin >> keepShopping;
keepShoppingcharkeepShoppingdoselection=cin.get（）Aifcingetline（）string str;
getline(cin, str);
keepShopping = str[0];
这将消耗您键入的所有内容，包括回车键，并且您不会得到这些奇怪的输入缓冲效果。使用
cin>getch（）；keepShopping = getch();
我不确定它位于哪个库中，但是像
#includegetch（）；keepShopping = getch();
我不确定它在哪个库中，但是像
#includestr[0]str[0]getchgetchargetchgetchgetchargetch