diff options
| -rw-r--r-- | 1-20_detab.c | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/1-20_detab.c b/1-20_detab.c new file mode 100644 index 0000000..3101610 --- /dev/null +++ b/1-20_detab.c @@ -0,0 +1,43 @@ +#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. + */ + +#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 { + // non-tabs simply get output. + putchar(c); + ++column; + // Line-endings should reset the column counter after being output. + if (c == '\n') { + column = 0; + } + } + } + return 0; +} |