Library Functions: getline( ) Function

getline( ) Function:

The getline( ) function is similar to gets() function. Both allow inputting a string. But gets( ) function works with standard input stream. Whereas getline( ) can work with cin object as well as with any other user-defined input stream object.

Another notable difference between these two function is, gets( ) function by default uses new-line (‘\n’) as a string terminator and leaves the character in the input stream. Whereas getline( ) function removes the terminating character (new-line by default)  from the input stream.

Moreover with the getline( ) function you have option to specify your own string terminating character, also the maximum number of characters form the line to pick. String terminates when specified maximum number of characters picked for the input stream or specified string terminating character is encountered in the input stream, whichever occurs earlier.

Syntax:

Device.getline(char_variable,integer_limit,“terminating_character");

Example 1:

Char name[30];

cin.getline(name, 20, ‘.’);

Here, the input will be terminated by the presence of (.) in the input stream or by maximum limit 19 no.of  characters, which ever occurs earlier. See the programs given below illustrating the use of getline( ).

Example 2

//Program demonstrating use of getline function with cin object

#include<iostream.h>

int main()

{

char buf[30];

cout<<"\n Enter a line and terminarte by .(dot): ";

cin.getline(buf,30,'.');

cout<<buf;

return 0;

}

Output:

RUN 1

In the first run dot (.) is considered as string terminator.

RUN 2

In second RUN 29 characters are accepted. Because a maximum limit was set to 30.

Example 3

/*Program demonstrating the use of getline with user define input stream which represents a disk file "myfile.txt"*/

#include<iostream.h>

#include<fstream.h>

#include<stdlib.h>

#include<conio.h>

int main()

{

clrscr();

char myline[70];

int LC=0;

ifstream infile("myfile.txt");

     if(!infile)

     {

     cerr<<"Filed to open the input file";

     exit(1);

     }

     while(1)

     {

     infile.getline(myline,70,'.');

     if(infile.eof()) break;

     LC++;

     cout<<LC<<": "<<myline<<'\n';

     }

infile.close();

getch();

return 0;

}

Output: