当使用带有int的getline时，如何修复“没有重载函数的实例”getline“匹配参数列表”

Question

Im currently working on an assignment and am trying to use try catch error handling for checking a user's input is a valid int.

I currently have this:

int inputValidation() {
    int e = 0;
    std::string es;
    bool check = false;
    do {
        try {
            if (!getline(std::cin, e)) {
                throw stringInput;
            }
            else {
                check = true;
            }
        }
        catch (std::exception& er) {
            std::cout << "Error! " << er.what() << std::endl;
            std::cin.clear();
            std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
        }
    } while (!check);
    return e;
}

my issue is with the if ((getline(std::cin, e))){} part. I've also tried using std::cin.getline(e, 256)

When calling the function I'm using this loop:

do {
        std::cout << "Please select a month: ";
        selectedMonth = inputValidation();
    } while (selectedMonth < 1 || selectedMonth >(12 - actualMonth));

This simply makes sure they can only input a month from the current month until December.

I'm aware that I can use es instead of e , however that defeats the purpose of the error checking. My only idea coming off of this is to check on a conversion.

For whatever reason I seem to be getting the error "no instance of overloaded function "getline"" and am unsure of where I'm going wrong. If anyone could provide some insight I would be very grateful.

Answer 1

if std::cin >> e is not appropriate, you could use istringstream :

std::string asText;

std::getline(cin,asText);

std::istringstream iss (asText);

if (iss >> e)

Answer 2

First Version

I managed to fix this by changing it to:

int inputValidation(std::string message) {
    int e = NULL;
    std::string es;
    bool check = false;
    do {
        try {
            std::cout << message;
            getline(std::cin, es);
            if (!atoi(es.c_str())) {
                throw stringInput;

            }
            else {
                e = atoi(es.c_str());
                check = true;
            }
        }
        catch (std::exception& er) {
            std::cout << "Error! " << er.what() << std::endl;
        }
    } while (!check);
    return e;
}
//In another function -->
    do {
        selectedMonth = inputValidation("Please select a month: ");
    } while (selectedMonth < 1 || selectedMonth >(12 - actualMonth));

Working Version

As of the comments I changed this.

(The only difference is this version doesn't include an exception)

bool checkInput(int &input, std::string message) {
    try {
        std::cin >> input;
        if (!std::cin.fail()) {
            return true;
        }
        else {
            throw(message);
        }
    }
    catch (std::string e) {
        std::cout << "Invalid input!" << std::endl;
        std::cout << e << std::endl;
        std::cin.clear();
        std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
        return false;
    }
}

//Elsewhere -->
std::cout << "Please input the lowest number you would like to check" << std::endl;
while (!checkInput(lowestNumber, "Please input the lowest number you would like to check"));