reading from stdin in c++

Question

I am trying to read from stdin using C++, using this code

#include <iostream> using namespace std;  int main() {     while(cin) {         getline(cin, input_line);         cout << input_line << endl;     };     return 0; } 

when i compile, i get this error..

[root@proxy-001 krisdigitx]# g++ -o capture -O3 capture.cpp capture.cpp: In function âint main()â: capture.cpp:6: error: âinput_lineâ was not declared in this scope 

Any ideas whats missing?

Answer 1

You have not defined the variable input_line.

Add this:

string input_line; 

And add this include.

#include <string> 

Here is the full example. I also removed the semi-colon after the while loop, and you should have getline inside the while to properly detect the end of the stream.

#include <iostream> #include <string>  int main() {     for (std::string line; std::getline(std::cin, line);) {         std::cout << line << std::endl;     }     return 0; }