Thread: Reverse the words of a sentence.

Well in your counting backward loop, all the interesting stuff seems to happen when you reach a space.

So perhaps do something when you hit a space.

Here's a fun thing to try
if ( array[count] == ' ' ) printf("%s\n", &array[count] );

Code:

#include <stdio.h>
int main(void)
{
  char ch , array[100]={'\0'};
  int i=0 ,  count;
  
  printf("Enter a sentence: ");
  
  while((ch=getchar())!='.' && ch != '?' && ch != '!' )
	  array[i++]=ch;
  
  for(count=0; count<i; count++)  
  printf("%c" , array[count]);
  
  putchar(ch);  // print single character 
  
  printf("\n Reversal of the words of the sentence: ");

  count=i-1;
  while( count >=0 )
  {
	  int j=0;
	  
	  if( ch == ' ')
	  putchar(ch);
	  
	  else
			{
				 array[j] = array[count];
				 ++j;
			 }
			 
		  count--;
  }

  putchar(ch);
	  
    return 0;
}

I want to solve the given exercise.

Why I don't take the proper result?

I give -> Hello man.
and take -> . (empty) why? :S

The problem is that the book does not have a solution... if it had I would have read it from there.

You need to toss this code out, grab a piece of paper, and think. Write out how to do it in English. There are a few possibilities. Here's one.

Use strtok to set spaces after words to '\0', saving the returned pointers in an array. Then go backwards through the pointer array, printing the words. You'll have to deal with end punctuation specially to keep it at the end (if that's what you want), and also change the case of the original first word to lower and the original last word to upper (if you want).

Originally Posted by Nyah Check

i think here you need two nested for loops one increments after it hits the ' ' and the other continues decrementing until it finds another ' ' or you create a two dimensional array that increments after the ' ' is entered and then increments the array.for example str[MAX][]; for ( ch = getc(stdin) == ' ') i++;str[i][m++] = ch; i think this may work.....

Well , thank you very much for your answer! I try to fix it with this ->

Code:

/* Αντιστροφή της σειράς των λεξεων μιας πρότασης
 *  INPUT : Hello man. 
 *  OUTPUT : man Hello.
 * */
 //---------------------------------------------------------------------
 
#include <stdio.h>
#include <ctype.h>

int main(void)
{
  char ch , array[100]={'\0'};
  int i=0 , count , j;
  
  printf("Enter a sentence: ");
  
  while((ch=getchar())!='.' && ch != '?' && ch != '!' )
  {
	  array[i++]=ch;
	  putchar(ch);
  }
   
  putchar(ch);  // print single character 
  
  printf("\n Reversal of the characters of the words of the sentence: ");
  
  for(count= i-1; count>= 0; count--)
  {
  
  if( array[count] == ' ' || count == 0 )
  {
        if(count == 0)
	   j=0;
	
	else
	j=count+1;  
	
	while(isalpha(array[j]))
	{
      printf("%c" , array[j]);
      ++j;
    
    }
     
    printf(" ");
 }

}
  
  putchar(ch);
	  
    return 0;
}
//----------------------------------------------------------------------
// An dwsw apostrofo tin trwei opws episis kai to keno stin arxi :/

Ignore my comments , They are in Greeks. (I can explain what I write if you want to of course!!!)

Anyway I have[s] two[/s] one problem... it doesn't print the apostrophe.

Do you have any idea in order to fix that without change the logic of my program??? (I mean not completely changes).

Thank you in advance for your time.

I thoroughly recommend the two-pass approach for this. It operates in place, and is a bijective transform!

Pass 1: Just reverse the whole string.
Pass 2: Locate the end of each backwards word and reverse that word back again.

Note that you can do the passes in either order too.
Oh and in your case I guess you would exclude the last character from any manipulation, if it is a punctuation character.