K&R Exercise 1-9 (C)

Question

\"Write a program to copy its input to its output, replacing each string of one or more blanks by a single blank.\"

I\'m assuming by thi

Answer 1

This is a solution using only the techniques described so far in K&R's C. In addition to using a variable to achieve a finite state change for distinguishing the first blank space from successive blank spaces, I've also added a variable to count blank spaces along with a print statement to verify the total number. This helped me to wrap my head around getchar() and putchar() a little better - as well as the scope of the while loop within main().

// Exercise 1-9. Write a program to copy its input to its output, replacing
//               each string of one or more blanks by a single blank.

#include 

int main(void)
{
    int blank_state;
    int c;
    int blank_count;

    printf("Replace one or more blanks with a single blank.\n");
    printf("Use ctrl+d to insert an EOF after typing ENTER.\n\n");

    blank_state = 0;
    blank_count = 0;
    while ( (c = getchar()) != EOF )
    {
        if (c == ' ')
        {
            ++blank_count;
            if (blank_state == 0)
            {
                blank_state = 1;
                putchar(c);
            }
        }
        if (c != ' ')
        {
            blank_state = 0;
            putchar(c);
        }
    }

    printf("Total number of blanks: %d\n", blank_count);

    return 0;
}