kdeng00
89 lines
1.7 KiB
C
89 lines
1.7 KiB
C
/*
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*
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* Exercise 1-20. Write a program detab that replaces the tabs in the input with the
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* proper number of blanks to space to the next tab stop. Assume a fixed set of tab
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* stops, say every n columns. Should n be a variable or a symbolic parameter?
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*
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* Author: Kun Deng
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*/
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#include <stdio.h>
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#define TAB_REPRESENTER 2 // Represents how many spaces a tab would equal
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#define LINE_MAX_LIMIT 1000
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char line[LINE_MAX_LIMIT];
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int line_length;
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int get_line(void);
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void replace_tabs(void);
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int main()
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{
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extern int line_length;
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printf("Enter a sequence of characters\n");
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printf("Any tabs will be replaced with %d white space characters\n", LINE_MAX_LIMIT);
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while (line_length = get_line())
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{
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printf("before: %s\n", line);
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replace_tabs();
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printf("after: %s\n", line);
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}
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return 0;
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}
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int get_line(void)
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{
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extern char line[];
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int i = 0;
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int c;
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for (; (c = getchar()) != EOF && c != '\n'; ++i)
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{
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line[i] = c;
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}
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line[i] = '\0';
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return i;
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}
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void replace_tabs(void)
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{
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extern char line[];
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extern int line_length;
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for (int i = 0; i != line_length; ++i)
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{
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char some_char = line[i];
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if (some_char == '\t')
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{
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int new_line_length = line_length + TAB_REPRESENTER;
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line[new_line_length] = '\0';
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for (int j = (line_length - 1); j > i; --j)
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{
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line[j + TAB_REPRESENTER] = line[j];
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}
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for (int k = i; k < (i + TAB_REPRESENTER); ++k)
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{
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line[k] = ' ';
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}
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line_length = new_line_length;
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line[i + TAB_REPRESENTER] = 127;
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}
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}
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}
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