/* gets() is on a stdin PIPE (at the time it is called) and is unsafe: Enter 19 characters, the stack canary lives. Enter 20+...the stack canary dies. Stack canaries are an important concept in information security. * Edit: Added a buffer to prevent "No Output" and garbage. =========================================== Q&A: Why am I not able to use gets and puts in my c++ program? I tried this simple program- https://www.sololearn.com/Discuss/443483/?ref=app A: because gets() is reading from a PIPE (as used here, the pipe needs data before your program starts) =========================================== You would normally 'echo' (or 'cat') like this: C:\>echo "Input stream" | myprogram.exe $ cat or_just_cat_a_file.txt | myprogram ...but you can use the pipe with gets() by positioning cin so it's discarded (below). */ #include #include #include using namespace std; int main() { cout<<"enter your name\n"; std::string buffer = " "; char canary[6] = "Alive"; char name[20]; /* Author got garbage because: "need to zero"... it doesn't take user's input rather it prints some random characters itself. Can you please tell what mistake I am making? */ for(int i=0; i<20; i++) { name[i]=0; } gets(name); // cin (below) got data on the pipe puts(name); if(canary == "Alive"){ cout << "The canary lives!!!"; // Frodo } else { cout << "Stack canary corrupted: "; } cout << " [" << canary << "]" << endl; // This doesn't cause a problem (here on SL)... // ...but it pops up input, for piping to gets() char whatever; std::cin>>whatever; // cout<

Using gets() + stack canary [fixed a crash]