Help with K&R Exercise 1.13

[Yannis]

Hello,

I just started delving into C and programming in general a few days ago with K&R and I'm struggling with exercise 1.13 (The Histogram). A bit too early to struggle eh? :P

Instead of horizontal asterisks I only get '0' which is the printlen[] initialization. I'm guessing I can't add characters the way I imagined?

This is what I've come up with so far and it compiles fine as is. Not sure if my thought process is correct here. I hope I'm on the right path at least.

#include <stdio.h>


int main(void)
{
	int printlen[10];
	int clen = 0;
	int c = 0;
	
	for(clen = 0; clen <= 10; ++clen) /* Initialize printlen array */
		printlen[clen] = 0;
			

	while ((c = getchar()) != EOF) /* Loop until EOF */
	{
		if ( c != ' ' || c != '\n' || c != '\t') /* Check start and end of word */
			++clen;
			
		printlen[clen] = '*' + printlen[clen]; /* Count '*' */
	}									
	
	printf("Length\n");
	for(clen = 0; clen < 10; ++clen)
		printf("  %d\t %c\n", clen, printlen[clen]);
	printf("  >10\t %c\n", printlen[clen]);

	return 0;
}

What I am guessing is going wrong is that it's not adding the '*' to the initialization of printlen[] in this line:

printlen[clen] = '*' + printlen[clen];

If I can get passed that I should be able to fix all the other 'bugs' in here.

Thanks for any advice on the matter.

Yannis

[Dave_Sinkula]

>for(clen = 0; clen <= 10; ++clen) /* Initialize printlen array */
> printlen[clen] = 0;

You are going one beyond the end of the array.

>if ( c != ' ' || c != '\n' || c != '\t') /* Check start and end of word */

This is always true.

>printlen[clen] = '*' + printlen[clen]; /* Count '*' */

It looks like you are attempting to do string concatentation with the above code; this is not the way to do it. You don't need to do string concatenation to solve this problem.

For additional help, take a look at this.

[twm]

You have the right idea:

#include <stdio.h>

void printhist(int lengths[]) {
  int i;
  int j;

  for (i = 0; i < 20; i++) {
    printf("%d\t", i+1);
    for (j = 0; j < lengths[i]; j++)
      putchar('*');
    putchar('\n');
  }
}

int main ( ) {
  int lengths[20] = {0}; /* Up to 20 characters */
  int currlen;           /* Current word length */
  int c;                 /* Current char taken from the stream */

  currlen = 0;
  while ((c = getchar()) != EOF) {
    if (c == '\n' || c == ' ' || c == '\t') {
      lengths[currlen-1]++;
      currlen = 0;
    }
    else
      currlen++;
  }
  printhist(lengths);

  return 0;
}