The file pointers are the means to access the file for reading and writing purposes. This section explains how to read values from the screen and how to print the result on the screen.

The int putchar(int c) function puts the passed character on the screen and returns the same character. This function puts only single character at a time. You can use this method in the loop in case you want to display more than one character on the screen. Check the following example:

#include <stdio.h>
int main( )
{
 int c;
 printf( "Enter a value :");
 c = getchar( );
 printf( "\nYou entered: ");
 putchar( c );
 return 0;
}

When the above code is compiled and executed, it waits for you to input some text. When you enter a text and press enter, then the program proceeds and reads only a single character and displays it as follows:

$./a.out
Enter a value : I am happy
You entered: I 

#include <stdio.h>
int main( )
{
 char str[100];
 printf("Enter a value :");
 gets( str );
 printf("\nYou entered: ");
 puts( str );
 return 0;
}

When the above code is compiled and executed, it waits for you to input some text. When you enter a text and press enter, then the program proceeds and reads the complete line till the end, and displays it as follows:

$./a.out
Enter a value : this is test 
You entered:this is test                                                                   

The format can be a simple constant string, but you can specify %s, %d, %c, %f, etc., to print or read strings, integer, character, or float, respectively. There are many other formattings options available which can be used based on requirements. Let us now proceed with a simple example to understand the concepts better:

#include <stdio.h>
int main( )
{
 char str[100];
 int i;
 printf( "Enter a value :");
 scanf("%s %d", str, &i);
 printf( "\nYou entered: %s %d ", str, i);
 return 0;
}                                                                                                                                                

When the above code is compiled and executed, it waits for you to input some text. When you enter a text and press enter, then program proceeds and reads the input and displays it as follows:

$./a.out
Enter a value : seven 7 
You entered: seven 7          

Here, it should be noted that scanf() expects input in the same format as you provided %s and %d, which means you have to provide valid inputs like "string integer". If you provide "string string" or "integer integer", then it will be assumed as wrong input. Secondly, while reading a string, scanf() stops reading as soon as it encounters a space, so "this is test" are three strings for scanf().