Structure of a C Program

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PDS: CS 11002 Computer Sc & Engg: IIT Kharagpur 1




File Access




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Lect 29 Goutam Biswas

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PDS: CS 11002 Computer Sc & Engg: IIT Kharagpur 2




Standard I/O

So far all our I/O operations are read from the
standard input (stdin - keyboard) and write to
the standard output (stdout - VDU) devices.
These are defined and connected to the running
program (process) by the OS.



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Lect 29 Goutam Biswas

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PDS: CS 11002 Computer Sc & Engg: IIT Kharagpur 3




stdin & stdout

In Unix/Linux operating systems these input
and output streams are treated as two files
stdin and stdout respectively. The printf(),
scanf() functions and the getchar(),
putchar() functions/macros are used to access
these files.



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Lect 29 Goutam Biswas

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PDS: CS 11002 Computer Sc & Engg: IIT Kharagpur 4




File Access Functions

But we like to open other files for read, write or
append. Following C library functions are used
for this purpose: fopen(), fclose(),
fseek(), fprintf(), fscanf(), getc(),
putc() etc.



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Lect 29 Goutam Biswas