unable to get input the proper way.

In c++, I want to input a string after I input a number.
This is my code.
Why string s doesn’t get any input?
What is the correct way of doing it?

Correct way-

    #include <iostream>
#include<string>
using namespace std;
int main() 
{
	int b;
	string s;
	cin>>b;
	cin>>s;
	cout<<b<<endl;
	cout<<s;
	return 0;
}

I suspect that whatever you are using to get the string input, is getting the null character/end line character and assigning it to string. Its pretty common error programmers do.

EDIT 1 - getline usually reads the entire line, including the new line character etc. So it accepts new line character as a valid input, which most other inputs methods/keywords (idk what to call them atm XD) usually don’t.

PS, I think you can find something good here-

stack overflow
stack overflow 2

The problem is that you are not flushing the newline (’
') character after cin>> statement.

so you must need to flush the newline character out of the buffer in between. You can do it by using cin.ignore(). This happens because the >> operator leaves a newline
character in the input buffer which which be taken by getline() prior to reading your next input.

Click here to see my code.

1 Like
  • First of all you have to understand
    how both cin>> and getline() works.

    cin>> starts working by first
    eliminating all white spaces and
    newline character. That’s why input
    like in one line

     45 98 65
    

    will be taken as 3 input. Why?, because cin>> will
    automatically terminate and stop
    taking input after getting any white
    space or newline character.

  • getline works differently. It takes
    any character at starting whether it
    is white space or newline. That’s why
    i had to include cin.ignore() to
    eliminate newline character. Another
    property of getline is it will only
    terminate after getting newline(’
    ')
    character.

2 Likes

Why doesn’t this happen when we try to input 2 int which are on different lines?


This works but the previous one doesn’t.

Even if I try it this way I only get the first word of the string as input.

Oh, so you want to input a sentence? It wont work for that. Try Bansal’s method for that. I saw no indication for sentence (strings with white spaces have different input that strings without white spaces)

using cin.ignore() is the way to go bud, cause cin>>s will stop at the first whitespace it encounters

Exactly what I had to say!! Well explained! :slight_smile:

1 Like

Nice Explanation. Thanks.