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

/*a program that copies its input to its output, replacing each string of one or more blanks by a single blank*/

#include <stdio.h>
#include<stdlib.h>

int main(void)
{
    double c;
    char blank = ' ';

    while((c = getchar()) != EOF)
    {
        if(c == ' ')                                
            {
            putchar(c);                             

                while(( c = getchar() )== ' ')      

                    {
                    if(c != ' ')                    
                    break;
                    }
            }




        if(c == '\t')                               
            {
                putchar(blank);                     
                    while((c = getchar()) == '\t')  

                    {
                    if(c != '\t')                   
                    break;
                    }
            }

    putchar(c);                                     
    }

return 0;
}

Answer 2

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 <stdio.h>

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;
}

Answer 3

#include <stdio.h>
main()
{
    int c, numBlank=0 ;
    while((c= getchar())!=EOF)
    {
        if(c ==' ')
    {
        numBlank ++;
        if(numBlank <2)
        {
        printf("character is:%c\n",c);
        }
    }
    else
    {
        printf("character is:%c\n",c);
        numBlank =0;
    }
    }
}

Answer 4

Same explanation with Matt Joiner's, but this code does not use break.

int c;

while ((c = getchar()) != EOF)
{
    if (c == ' ') /* find a blank */
    {
        putchar(' '); /* print the first blank */
        while ((c = getchar()) == ' ') /* look for succeeding blanks then… */
            ; /* do nothing */
    }

    if (c != EOF) /* We might get an EOF from the inner while-loop above */
        putchar(c);
}

Answer 5

a way to make it easier for the new people are stuck on this book (by not knowing any thing then what brought up until page 22 in K&R).

credits to @Michael , @Mat and @Matthew to help me to understand

#include <stdio.h>
main()
{
 int c;

while ((c = getchar()) != EOF) /* state of "an input is not EOF" (1) */ 
 {
        if (c == ' ') /* "blank has found" -> change the rule now */
        {
          while ((c = getchar ()) == ' '); /* as long you see blanks just print for it a blank until rule is broken (2) */
          putchar(' ');
        }
   putchar(c); /* either state (2) was broken or in state (1) no blanks has been found */
  }
}

Answer 6

I am at the same point in the book. and my solution goes with making a count++ if blank is found and making the count back to zero if anything other than blank is found.

For if statement I put another another check to check value of count (if zero) and then print.

Though at this point of learning I shouldn't be concern about efficiency of two methods but which one is efficient a.) Accepted solution here with while inside while or b.) the one I suggested above.

My code goes like below:

#include <stdio.h>


main()
{
    int count=0,c;
    for( ; (c=getchar())!=EOF; )
    {
        if(c==' ')
        {
            if(count==0)
            {
                putchar(c);
                count++;
            }
        }
        if(c!=' ')
        {
            putchar(c);
            count=0;
        }


    }
}