detab.c

/* head */
#include            <stdio.h>
#define        LINEMAX        1000
#define        TABSTOP        8

/* external variables */
char str[LINEMAX];
int charcount = 0;


/* function prototypes */
void getstr(void);
void putstr(void);


/* body */
main(){

    int n = 0;
    int stop;

    getstr();
    putstr();

}


/* function definitions */
void getstr(void){

    char c;
    int n;

    for( n = 0; ( c = getchar() ) != EOF && c != '\n'; ++n ){
        str[n] = c;
    }

    if( c = '\n' ){
        str[n] = c;
        ++n;
    }

    str[n] = '\0';

}

void putstr(void){

    int n;
    char c;

    for( n = 0; ( c = str[n] ) != '\0'; ++n ){
        int space = ( TABSTOP - ( charcount % TABSTOP ) );
        int loop;
        if( c == '\t' ){
            for( loop = 0; loop < space; ++loop){
                putchar(' ');
            }

            charcount = charcount + space;
/*            putchar('\t');

            printf("%d,%d", charcount, space );
*/        }
        else{
            putchar(str[n]);
            ++charcount;
        }

    }

}