Question

我有一份上学的任务，非常简单，只是从一个联合中心订购汉堡并计算成本。我已经尝试使用if语句来确保用户喜欢他们的订单，但它一直给我和错误，无论我的变量＆＃34; yesorno＆＃34;是字符串或字符。

#include <cstdlib>
#include <iostream>
#include <string>
using namespace std;

int main() {
char yesorno;
int burgers, fries, drinks;
int i=0;
while (i=0) {
    cout<<"Aidan: 'Welcome to the Christopher Burger Joint!\nOur burgers are $4.00, fries are $2.50, and drinks are $1.50.";

    cout<<"\nHow many burgers will you be having today?";
    cin>>burgers;
    cout<<"\nHow many fries will you be having today?";
    cin>>fries;
    cout<<"\nand how many drinks for you today?";
    cin>>drinks;
    cout<<"\nSo here is your current order:\nBurgers: "<<burgers<<"\nFries: "<<fries<<"\nDrinks: "<<drinks;
    cout<<"Is this all?\nYes or No: ";
    cin>>yesorno;
    if (yesorno = "yes") {
        i=2;
    }

}
int grosstotal = (burgers*4)+(fries*2.5)+(drinks*1.5);
int tax = grosstotal*.12;
int total = tax+grosstotal;
cout<<"\nYour total before tax is $"<<grosstotal<<",\nYour tax is $"<<tax<<",\nAnd your total today is $"<<total<<".\nEnjoy!'";


return 0;
}

Answer 1

对于初学者来说，在while语句中有赋值而不是比较

while (i=0) {
       ^^^

在此if语句中

if (yesorno = "yes") {
           ^^^

再次分配而不是比较。

要从用户接受类似"yes"的字符串，变量yesorno应声明为类型为std::string。

而不是while循环，最好使用do-while循环。例如

int main() {
    string yesorno;
    int burgers, fries, drinks;

    do {
        //...

        cin>>yesorno;
    } while ( yesorno != "yes" );

此外，您可以删除标头<cstdlib>，因为标头中的声明都未在程序中使用。

Answer 2

#include <cstdlib>
#include <iostream>
#include <string>
using namespace std;

int main() {
    string yesorno;
    int burgers, fries, drinks;
    int i=0;
    while (i==0) {
        cout<<"Aidan: 'Welcome to the Christopher Burger Joint!\nOur burgers are $4.00, fries are $2.50, and drinks are $1.50.";

        cout<<"\nHow many burgers will you be having today?";
        cin>>burgers;
        cout<<"\nHow many fries will you be having today?";
        cin>>fries;
        cout<<"\nand how many drinks for you today?";
        cin>>drinks;
        cout<<"\nSo here is your current order:\nBurgers: "<<burgers<<"\nFries: "<<fries<<"\nDrinks: "<<drinks;
        cout<<"Is this all?\nYes or No: ";
        cin>>yesorno;
        if (yesorno == "yes") {
            i=2;
        }

    }
    int grosstotal = (burgers*4)+(fries*2.5)+(drinks*1.5);
    int tax = grosstotal*.12;
    int total = tax+grosstotal;
    cout<<"\nYour total before tax is $"<<grosstotal<<",\nYour tax is $"<<tax<<",\nAnd your total today is $"<<total<<".\nEnjoy!'";


     return 0;
}

这对我有用。你错过了几个==。

Answer 3

实际上你正在为变量yesorno分配字符串yes，你在那里做错了=是一个用于比较的赋值运算符==用于比较所以insted

  if (yesorno = "yes") {
        i=2;
    }

写

if (yesorno == "yes") {
    i=2;
}

不能把if语句放在循环C ++中

3 个答案: