I thought I'd have a play with C++ on the Pico so loaded the following simple program. I'm a complete beginner at C++
This works perfectly as expected if I enter a number. If I enter a letter the program immediately prints 0 which is correct but then, irrespective of what way I try and clear the input stream, it loops continuously printing 0.
I've google clearing cin and tried a range of variants: cin.sync(), cin.ignore(), std::cin.ignore(std::numeric_limits<std::streamsize>::max(),'\n')
It only does what I want if I add
fflush(stdin);
after the cin.clear
But, as I understand it, this shouldn't be necessary and google suggests will make the code non-portable by using a function with an undefined result
Code:
#include <stdio.h>#include "pico/stdlib.h"#include <iostream>int main(){ stdio_init_all(); busy_wait_ms(1000); while(1) { std::cout << "Enter a number: "; // ask user for a number int x{}; // define variable x to hold user input std::cin >> x; // get number from keyboard and store it in variable x std::cin.clear(); //get rid of anything else in the input std::cout << "You entered " << x << '\n'; } }I've google clearing cin and tried a range of variants: cin.sync(), cin.ignore(), std::cin.ignore(std::numeric_limits<std::streamsize>::max(),'\n')
It only does what I want if I add
fflush(stdin);
after the cin.clear
But, as I understand it, this shouldn't be necessary and google suggests will make the code non-portable by using a function with an undefined result
Statistics: Posted by matherp — Sat Jan 04, 2025 1:37 pm — Replies 3 — Views 74