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#include <stdio.h>
/* The C Programming Language: 2nd Edition
*
* Exercise 1-20: Write a program `detab` that replaces tabs in the input with
* the proper number of blanks to space to the next tabstop. Assume a fixed set
* of tabstops, say every 'n' columns. Should 'n' be a variable or a symbolic
* parameter?
*
* Answer: 'n' should be a symbolic parameter. It's more apparent what's being
* worked with and it's not susceptible to scope. Though, in this simple
* program it really doesn't matter.
*
* The "correct" solution uses the isprint() stdlib function, but it's not
* covered by this point in the book, so I did not use it.
*/
#define TABWIDTH 8
int main(void) {
int column, c;
column = 0;
while ((c = getchar()) != EOF) {
// Be sure that the character is a tab
if (c == '\t') {
/*
* Divide a line by TABWIDTH and you have your tabstops. If you
* modulo by TABWIDTH and it equals 0, you've reached a tabstop and
* don't need to output more spaces!
*/
while (column % TABWIDTH != 0 && column != 0) {
putchar(' ');
++column;
}
} else {
if (c == '\n') {
// Line-endings should reset the column counter after being output.
putchar(c);
column = 0;
} else {
// Now we can just output and increase column!
putchar(c);
++column;
}
}
}
return 0;
}
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