ch01/ex20-detab.c


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#include <stdio.h>

#define TABSTOP 8  /* number of columns between tab stops */

void putspace(int len);


/* replace tabs with proper spaces */
int main()
{
    int c;
    int col;
    int nspace;

    col = 0;
    while ((c = getchar()) != EOF) {
        if (c == '\t') {
            nspace = TABSTOP - (col % TABSTOP);
            col = col + nspace;
            putspace(nspace);
        } else if (c == '\n') {
            col = 0;
            putchar(c);
        } else {
            ++col;
            putchar(c);
        }
    }

    return 0;
}

/* print len spaces */
void putspace(int len)
{
    int i;

    for (i = 0; i < len; ++i)
        putchar(' ');
}