File Access

The stdio.h contains a typedef¹ of a struct² called FILE.
The fopen(const char*, const char*) function takes two arguments.

1. Name of the file to be opened.
2. The mode in which file needs to be opened in.
   • r for read.
   • w for write.
   • a for append.

If there is any error while opening the file, fopen(const char*, const char*) returns NULL.
There are two other functions as well.

int getc(FILE* file_ptr); // (1)!
int putc(char c, FILE* file_ptr); // (2)!

1. Gets a char and moves the pointer one character ahead in the buffer in which file's contents exist.
2. Writes a char to the buffer containing file's contents.

There are 3 const file pointers which are opened by the Operating System when a C program is ran.

• stdin
• stdout
• stderr

Then, fclose(FILE*) is used to disconnect the program from the file.

References

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1. Read more about typedef. ↩

2. Read more about structs. ↩