Summary of use of CIN in C + +

When you learn C + +, you must be confused about the functions of the input and output functions, now to summarize the simple use of various functions.

CIN has a buffer, the input buffer, that is built. The first input process is this, when the input data is stored in the input buffer at the end of the keyboard input, and the CIN function takes the data directly from the input buffer. Because the CIN function takes data directly from the buffer, sometimes when there is residual data in the buffer, the CIN function directly obtains the residual data without requesting the keyboard input, which is why sometimes the input statement fails.

Usage of the 1.cin>> function: This is the input stream we use most often to learn the initial contact of C + +.

　　Usage 1. Accepts the input of a string and encounters a "Space" "tab" "Enter" end.

#include <iostream>
using namespace Std;
void Main ()
{
Char a[10];
cin>>a;
cout<<a<<endl;
}

Input: AAABBBCCC

Output: AAABBBCCC

Input: AAA BBB CCC

Output: AAA

2. Enter a number.

#include <iostream>
using namespace Std;
void Main ()
{
int A, B;
cin>>a>>b;
cout<<a+b<<endl;

}

Input: 1 return car 2 return car

Output: 3

The use of 2.cin.get (), this function has three forms, Cin.get (), Cin.get (char ch), Cin.get (array,length).

　　Usage 1.cin.get ()

Used to read a character, the end condition is carriage return, but does not discard the buffer's carriage return (enter) and the space, Cin.get () and Cin.get (char ch) function basically the same, char = Cin.get () and Cin.get (char ch) are the same.

#include <iostream>
using namespace Std;
int main ()
{
Char c,ch;
c = Cin.get ();
Cin.get (CH);
cout<<c<<endl;
cout<<ch<<endl;
return 0;
}

Input: A return (enter a character and then enter)

Output: A

(One line here)

Input: ABCD return

Output: A

B

Usage 2.cin.get (char ch) Usage 1

Usage 3.cin.get (array,length) accepts the input of a string, accepts the input length-1 characters, and the last deposit is ' \ s '.

#include <iostream>
using namespace Std;
int main ()
{
Char ch[10];
Cin.get (ch,5);
cout<<ch<<endl;
return 0;
}

Input: ABCDEFG return

Output: ABCD

　　The use of 3.cin.getline (), which accepts a string of input including a space, encounters a carriage return stop.

Usage 1.cin.getline ()

#include <iostream>
using namespace Std;
int main ()
{
Char ch[10];
Cin.getline (ch,5);
cout<<ch<<endl;
return 0;
}

Input: AAAAAAAA

Output: AAAA

The 4.getline () function, which accepts a string input containing a space, encounters a carriage return stop to include #incldue<string>.

Usage 1.getline (cin,sting s)

#include <iostream>
#include <string>
using namespace Std;
int main ()
{
string S;
Getline (cin,s);
cout<<s<<endl;
return 0;
}

Input: ABCDEFG return

Output: ABCDEFG

The 5.gets () function, which accepts a string input containing a space, encounters a carriage return stop, to contain #incldue<string>.

Usage 1: Receives input from a string.

#include <iostream>
#include <string>
using namespace Std;
int main ()
{
Char ch[10];
Gets (CH);
cout<<ch<<endl;
return 0;
}

Input: ABCDEFG return

Output: ABCDEFG

6.getchar () accepts a character input, contains spaces, and encounters a carriage return stop, to include #incldue<string>.

Usage 1: Accept input of one character

#include <iostream>
#include <string>
using namespace Std;
int main ()
{
Char ch;
ch = getchar ();
cout<<ch<<endl;
return 0;
}

Input: ABC return

Output: A

Summary of use of CIN in C + +