#include <stdio.h>

#define MAXLINE 1000  // maximum input line length
#define TABSIZE 8     // tab size

int getline(char* line, int maxline);
void detab(char* line, int tabsize);

// replaces tabs in the input with the proper number of spaces
// to the next tab stop
int main()
{
    int len;                // current line length
    char line[MAXLINE];     // current input line

    while ((len = getline(line, MAXLINE)) > 0)
    {
        if (len > 0)
            detab(line, TABSIZE);
        printf("%s", line);
    }

    return 0;
}

// getline: read a line into s, return length
int getline(char* s, int maxline)
{
    int c, i, j;

    for (i = 0, j = 0; (c = getchar()) != EOF && c != '\n'; ++i)
        if (j < maxline - 2)  // 2 bytes reserved for '\n' and '\0'
            s[j++] = c;

	if (c == '\n')
    {
        s[j++] = c;
        ++i;
    }

	s[j] = '\0';
    return i;
}

// detab: replaces tabs in the input with the proper number of spaces
// to the next tab stop
void detab(char* s, int tabsize)
{
    int i = 0;         // advance from s[0]
    int j = 0;
    int k;

    while (s[j]) ++j;  // points to '\0'

	while (s[i])
    {
        if (s[i] == '\t')
        {
            int insert = tabsize - i % tabsize - 1;
            for (k = j; k > i; --k)
                s[k + insert] = s[k];
            for (k = 0; k <= insert; ++k)
                s[i + k] = ' ';
            i += insert + 1;
            j += insert;
        }
        else
            ++i;
    }
}