当我超过第一个getline（）输入中的数组大小时，第二个getline或其他输入函数不起作用

Question

#include <iostream> 
#include <string.h>
#include<stdio.h>
using namespace std;

int main() 
{
char d,a[9],e[9];

cin.getline(a,9);
cin.getline(e,9);
cin>>d;
puts(a);
puts(e);
cout<<d<<endl;
return 0}

when i enter "hey every one" on the output screen, puts(e) prints a blank line and d prints a random character.second getline function and cin function is not working because of first getline . Thanks in advance.

Answer 1

You should read some documentation for the stuff you use:

After constructing and checking the sentry object, extracts characters from *this and stores them in successive locations of the array whose first element is pointed to by s, until any of the following occurs (tested in the order shown):
- [...]
- count-1 characters have been extracted ( in which case setstate(failbit) is executed ).

(Emphasize mine)

So the first getline fails if the input is too long and thus leaves std::cin in a bad (ie unreadable) state. This makes all successive input operations fail immediately.

---

Remark: To avoid tons of ugly trouble, you should avoid using C-style strings and the "kind of C-style" member- getline and just use std::string and the non-member std::getline instead.

Answer 2

When you use

cin.getline();

and when you press Enter after entering the string, that enter goes into the next string.

In order to prevent it, use cin.ignore();

It ignores the Enter and prevents it from entering into another string.

Here is your modified code:

#include<iostream> 
#include <cstring>
using namespace std;

int main() 
{
char d,a[9],e[9];
cout<<"String:"<<endl;
cin.getline(a,9);
cin.ignore();
cout<<"String:"<<endl;
cin.getline(e,9);

cin>>d;
cout<<a;
cout<<e;
cout<<d<<endl;
return 0;
}