Question

循环应接收输入，直到给出q或Q.虽然循环需要一个整数，但char q或Q会破坏循环并且无法识别。如何让循环识别q或Q来打破循环？

int ReadInput;      // Remembers input elements given
string ReadInputString = to_string(ReadInput); // String version of the ReadInput 

        do
        {
            bool NoErrors = true;   // Make sure there were no errors while reading input

            std::cout << "Enter the next element (Enter 'q' to stop): "; // Prompt user for input
            cin >> ReadInput;

            if (ReadInputString == quit || ReadInputString == Quit) // Enter Q or q to quit
            {
                break;
            }

            /* Validation */
            if (cin.fail()) 
            {
                /* Pass by the bad input */
                NoErrors = false; // Note there was a problem
                cin.clear(); // Clear the bad input
                cin.ignore(); // Ignore the bad input
                std::cout << "Invalid number" << endl; // Error message
            }

            /* Add the input to the list (if there were no problems) */
            if (NoErrors)
            {
                NumbersList.push_back(ReadInput); // Put the given number onto the end of the list
            }

        } while (ReadInput >= 0);

Answer 1

最后在哪里存储数字并不重要。你在整数变量中输入并期望将char存储在那里。所以只需要在那里取一个字符，检查它是否包含数字，如果是，则将其转换为num并继续，如果是char检查它是q或Q并且如果是则中断

int ReadInput;

char temp;

string ReadInputString = to_string(ReadInput); // String version of the ReadInput 

        do
        {
            bool NoErrors = true;   // Make sure there were no errors while reading input

            std::cout << "Enter the next element (Enter 'q' to stop): "; // Prompt user for input

            cin >> temp;                        //store input as char 
            if (isdigit(temp))                  //check input is number or not
                ReadInput = temp;               //convert input to num if true
            else if (temp == 'q' | temp == 'Q') //if not number check for q or Q
                break;                          //break if q

            if (ReadInputString == quit || ReadInputString == Quit) // Enter Q or q to quit
            {
                break;
            }

            /* Validation */
            if (cin.fail()) 
            {
                /* Pass by the bad input */
                NoErrors = false; // Note there was a problem
                cin.clear(); // Clear the bad input
                cin.ignore(); // Ignore the bad input
                std::cout << "Invalid number" << endl; // Error message
            }

            /* Add the input to the list (if there were no problems) */
            if (NoErrors)
            {
                NumbersList.push_back(ReadInput); // Put the given number onto the end of the list
            }

        } while (ReadInput >= 0);

C ++循环收到整数，直到给定Q.

1 个答案: