c_ch01_ex18.c

/*Exercise 1-18. Write a program to remove trailing blanks and tabs from each line of input, and to delete entirely blank lines.*/
#include <stdio.h>
#define MAX     1000
int untrail(char str[], int length);
int main()
{
        int length;
        length = 0;
        char str[MAX];
        while ((length = untrail (str, MAX)) > 0)
                printf ("%s\n", str);
        return 0;
}
int untrail(char str[], int length) {
        int c, i, j, flag;
        i = j = flag = 0;
        while ((c = getchar()) != EOF && c != '\n' && i < length - 1) {
                if (c == ' ' || c == '\t') {
                        flag = 1;
                        j += 1;
                } else {
                        flag = 0;
                        j = 0;
                }
                str[i++] = c;
        }
        if (flag) {
                str[i - j] = '\0';
                return j;
        } else {
                str[i] = '\0';
                return i;
        }
}