#include using namespace std; bool readInteger(int &number) { if (!(cin >> number)) { return false; } // 数字后应是空白或输入结束，防止把 2.5 读成 2。 int next = cin.peek(); return cin.eof() || next == ' ' || next == '\n' || next == '\t' || next == '\r'; } int main() { cout << "========================================\n"; cout << " 校园义卖找零助手\n"; cout << "========================================\n\n"; cout << "[1/3] 设置零钱\n"; cout << " 按 10 元、5 元、1 元的顺序输入库存张数。\n"; int stock10, stock5, stock1; while (true) { cout << " 库存张数 > "; if (readInteger(stock10) && readInteger(stock5) && readInteger(stock1) && stock10 >= 0 && stock10 <= 999 && stock5 >= 0 && stock5 <= 999 && stock1 >= 0 && stock1 <= 999) { break; } if (cin.eof()) { return 0; } cout << " ! 每种零钱请输入 0~999 张，用空格隔开。\n"; cin.clear(); while (cin && cin.get() != '\n') { } } cout << "\n[2/3] 录入商品\n"; cout << " 金额按整数元填写。\n"; int itemKinds; while (true) { cout << " 商品种数（1~10）> "; if (readInteger(itemKinds) && itemKinds >= 1 && itemKinds <= 10) { break; } if (cin.eof()) { return 0; } cout << " ! 请输入 1~10 之间的整数。\n"; cin.clear(); while (cin && cin.get() != '\n') { } } cout << "\n 输入单价和数量，中间留一个空格。\n"; int total = 0; for (int i = 1; i <= itemKinds; ++i) { int price, quantity; while (true) { cout << " 商品 " << i << '/' << itemKinds << " 单价数量 > "; if (readInteger(price) && readInteger(quantity) && price >= 1 && price <= 1000 && quantity >= 1 && quantity <= 100) { break; } if (cin.eof()) { return 0; } cout << " ! 单价请输入 1~1000 元，数量请输入 1~100 件。\n"; cin.clear(); while (cin && cin.get() != '\n') { } } int subtotal = price * quantity; total += subtotal; cout << " 小计 " << subtotal << " 元\n"; } cout << "\n[3/3] 收款\n"; cout << " 商品合计 " << total << " 元\n"; int paid; while (true) { cout << " 实收金额 > "; if (readInteger(paid) && paid >= 0 && paid <= 1000000) { break; } if (cin.eof()) { return 0; } cout << " ! 请输入 0~1000000 元之间的整数。\n"; cin.clear(); while (cin && cin.get() != '\n') { } } if (paid < total) { cout << "\n [未结算] 还需支付 " << total - paid << " 元。\n"; return 0; } if (paid == total) { cout << "\n [已结算] 金额正好，无需找零。\n"; return 0; } int change = paid - total; int remaining = change; int use10 = 0, use5 = 0, use1 = 0; // 先拿大面额。每拿一张，就扣掉对应的待找金额。 while (remaining >= 10 && use10 < stock10) { remaining -= 10; ++use10; } while (remaining >= 5 && use5 < stock5) { remaining -= 5; ++use5; } while (remaining >= 1 && use1 < stock1) { remaining -= 1; ++use1; } cout << "\n+-------------- 找零小票 --------------+\n"; cout << " 应收金额"; cout.width(9); cout << total << " 元\n"; cout << " 实收金额"; cout.width(9); cout << paid << " 元\n"; cout << " 应找金额"; cout.width(9); cout << change << " 元\n"; cout << " ------------------------------------\n"; if (remaining == 0) { cout << " [10 元] x " << use10 << " 张\n"; cout << " [ 5 元] x " << use5 << " 张\n"; cout << " [ 1 元] x " << use1 << " 张\n"; cout << "\n [已结算] 请按小票上的张数找零。\n"; } else { cout << " [未结算] 零钱不足，还差 " << remaining << " 元。\n"; cout << " 补充零钱后可重新结算。\n"; } cout << "+--------------------------------------+\n"; return 0; }