Character Input and symbol constant EOF in C Language

Source: Internet
Author: User

My system is centos5.5 and the compiler is GCC 2.5.

The procedure is as follows:

// Function of the program: verification expression getchar ()! = Whether the value of EOF is 0 or 1.

# Include <stdio. h>

Main ()


Int C;

While (C = getchar ()! = EOF )//! The = Priority is higher than the = priority, so the expression is combined from right to left.

Printf ("% d \ n", C );

Printf ("% d-at EOF \ n", C );


After GCC compilation, generate the. Out file.

./A. Out: Enter the following data:

2 press ENTER




How can two 1 s be output? Think about it, the carriage return is also a character, so it is actually two inputs, so the output is two 1. It also indicates that when the input is not equal to EOF, the expressionGetchar ()! = EOFThe value is 1.





Enter-1 and press Enter.





'-', 1, and 'Carriage return 'are three characters in total, SO 3 are output.

How can I end the input at this time? In my system, press Ctrl + D.

Press Ctrl + D, which is equivalent to the input EOF, and the output is:

0-at EOF

This indicates that when the input is equal to EOF, the expressionGetchar ()! = EOFThe value is 0.

Because EOF is defined in the header file <stdio. h>, you can add the following code to the end of the program to view the value of EOF:

Printf ("% d \ n", EOF );

The output result is-1.

Well, make a little progress every day.

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