cin

问题 I would like to know if it's possible to have multiple while (cin>>(variable)) as in the following code: #include <iostream> #include <vector> using namespace std; int main() { vector<int> v1, v2; int input; while (cin>>input) v1.push_back(input); while (cin>>input) v2.push_back(input); return 0; } The logic of my program is to let user define the number of elements and value of each element in two sets of int vectors. However, I realized that after entering the first set of numbers for the

问题 I had a strange behavior in a program and I spent long time trying to deduce why. it was an infinite loop with no sense. Testing these lines of code(under suspicion) i got the same result. Every time I type in a non-numeric value such a symbol, the program runs through an infinite loop printing zeros, which i guess is how cout represents the wrong value entered. I'd like to know why is that weird behavior from cin, printing all those zeros instead of stopping when it finds a wrong reading.

问题 I had a strange behavior in a program and I spent long time trying to deduce why. it was an infinite loop with no sense. Testing these lines of code(under suspicion) i got the same result. Every time I type in a non-numeric value such a symbol, the program runs through an infinite loop printing zeros, which i guess is how cout represents the wrong value entered. I'd like to know why is that weird behavior from cin, printing all those zeros instead of stopping when it finds a wrong reading.

问题 I have a class in c++ called Airplane. I need to create a read function using std::istream that lets a user type after a prompt in the console a line that is comma separated. This line of input will then be split up using the commas and assigned to different private data members of the class. As an example, if the user types into the console "abc,12345,hello," then I would need to parse that line and assign abc to one variable, 12345 to another and hello to the last. I believe after the user

问题 I am writing a software that grabs a password using std::cin However unlikely, i am trying to avoid the possibility that the password get paged to the disk from memory so I want to modify the buffer of std::cin to overwrite the password as soon as I'm done with it. right now i have this: std::cin.clear(); std::stringstream ss; ss << "0000000000000000000000000000000000000000000000"; std::cin.rdbuf(ss.rdbuf()); std::cin.clear(); but I'm pretty sure this is bad since it doesn't take into account

问题 I recently bought a C++ Primer and got stuck with a problem. I have to read a sequence of words using cin and store the values in a vector . After having unusual problems, I found out that while(cin >> words) invites problems (like infinite loop) if you expect invalid inputs: Using cin to get user input int main() { string words; vector<string> v; cout << "Enter words" << endl; while (cin >> words) { v.push_back(words); } for(auto b : v) cout << b << " "; cout << endl; return 0; } Therefore,

问题 I recently bought a C++ Primer and got stuck with a problem. I have to read a sequence of words using cin and store the values in a vector . After having unusual problems, I found out that while(cin >> words) invites problems (like infinite loop) if you expect invalid inputs: Using cin to get user input int main() { string words; vector<string> v; cout << "Enter words" << endl; while (cin >> words) { v.push_back(words); } for(auto b : v) cout << b << " "; cout << endl; return 0; } Therefore,

来源： https://stackoverflow.com/questions/25925290/c-round-a-double-up-to-2-decimal-places

问题 I have a question on some commands for cin. I'm still very new to c++ so bear with me. I'm doing a simple calculation program where the user inputs a value and the program does a calculation with the input. I'm attempting to create a loop that checks the input to ensure the user inputted and number. After some research I found that using cin.clear and cin.ignore will clear the previous input so the user can input a new value after the loop checks to see if its not a number. It works well,

问题 I have a question on some commands for cin. I'm still very new to c++ so bear with me. I'm doing a simple calculation program where the user inputs a value and the program does a calculation with the input. I'm attempting to create a loop that checks the input to ensure the user inputted and number. After some research I found that using cin.clear and cin.ignore will clear the previous input so the user can input a new value after the loop checks to see if its not a number. It works well,