c++ - stoi "terminate called after throwing an instance of ' std::无效参数'

Question

我目前正在研究一个动态编程问题，我决定用 C++ 而不是我常用的 Java/C# 来编写它来提高我的技能。但是，我收到一个我无法弄清楚的错误。编辑:我将在这里发布我的整个解决方案:

int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */
    int linecounter = 0;
    int value = -1;
    int differentCoins = -1;
    int uniqueCoinCount = -1;
    std::vector<std::vector<int>> array;
    int *uniqueCoins;
    int totalAmount = -1;

    for (std::string line; std::getline(std::cin, line); ) {
        if (linecounter % 2 == 0) {
            string inputs[2];
            int i = 0;
            stringstream ssin(line);
            while (ssin.good() && i < 2){
                ssin >> inputs[i];
                ++i;
            }
            cout << inputs[0];
            cout << inputs[1];
            totalAmount = std::stoi(inputs[0]);
            uniqueCoinCount = std::stoi(inputs[1]);
            uniqueCoins = new int[uniqueCoinCount + 1];

        }
        if (linecounter % 2 == 1) {
            array.resize(uniqueCoinCount + 1, std::vector<int>(totalAmount + 1));
            for (int i = 0; i < totalAmount; i++) {
                array[i][0] = 0;
            }
            for (int i = 0; i <= uniqueCoinCount; i++) {
                array[0][i] = 1;
            }


            stringstream ssin(line);
            int coinCounter = 0;
            uniqueCoins[coinCounter] = 0;
            coinCounter++;
            while (ssin.good() && coinCounter < uniqueCoinCount + 1){

                ssin >> uniqueCoins[coinCounter];
                coinCounter++;
            }

            for (int i = 1; i < totalAmount; i++) {
                for (int j = 1; j <= uniqueCoinCount; j++) {
                    int totalExcludingCoin = array[i][j - 1];
                    if (uniqueCoins[j] <= i) {
                        array[i][j] = totalExcludingCoin + array[i - uniqueCoins[j]][j];
                    }
                    else {
                        array[i][j] = totalExcludingCoin;
                    }
                }
            }
        }
        linecounter++;
    }

    //cout << array[totalAmount][uniqueCoinCount + 1];
}

当我使用 cout << inputs[0] 时, 我可以看到它打印出 4 .然而，hackerrank 编译器给我一个错误提示

"terminate called after throwing an instance of 'std::invalid_argument'
what(): stoi"

可能是什么问题？我也试过 atoi() ，返回我 40而不是 4 ，可能是由于 atoi返回 0什么时候出错？是因为它读取了空终止符还是什么？

谢谢

这是 hackerrank 上的输出:

Nice try, but you did not pass this test case.Input (stdin)4 31 2 3 Your Output (stdout)43Expected Output4Compiler MessageAbort CalledError (stderr)terminate called after throwing an instance of 'std::invalid_argument'  what():  stoi

Answer 1

        while (ssin.good() && i < 2){
            ssin >> inputs[i];
            ++i;
        }

您正在使用状态报告功能来预测 future 。 good 函数不会告诉您 future 操作的结果是什么，只会告诉您过去操作的结果。您需要实际检查操作 (ssin >> inputs[i]) 是否成功，而不是假设如果流在过去是好的，它就一定会成功。