CODEWITHSUNDEEP
c++windows
Mr. Perfectionist
Mr. Perfectionist

Reputation: 2746

How Ctrl Z works actually

Just for curious mind. During problem solving many question says,"Input will be terminated by Ctrl+z". I know its "EOF(End Of File)" But...

while(scanf("%d",&a)==1)
{ cout<<"OK"<<endl;}

while(scanf("%d",&a)!=EOF)
{cout<<"OK"<<endl;}

while(cin>>a)
{cout<<"OK"<<endl;}

Above 3 will be terminated by Ctrl+z.

while(scanf("%d",&a))
{cout<<"OK"<<endl;}

It will give OK by pressing Ctrl+z. and

while(1){cin>>a;
cout<<"OK"<<endl;}

Its a infinte loop.

I want to know how Ctrl+z works on a program termination. What is the reason behind it. Please answer in details.

Upvotes: 0

Views: 4806

Answers (1)

Adam Leggett
Adam Leggett

Reputation: 4113

Ctrl+z does not terminate your program. It also doesn't pause its execution. It's a 0x1A byte that is interpreted by iostream and stdio methods to be EOF (end-of-file). After that character is read from the console, nothing is read further and the method that is reading it returns. In the case of iostream, std::ios::eof() becomes true.

You would notice in your last case that if you structured it as:

while(cin >> a) { ... }

It would exit like the others.

Upvotes: 2

Related Questions