如何找到字符串中每个单词的长度？

Question

I wrote a code that takes a sentence and outputs every each word in a line. But I also want to write the size of each word next to it.

Input:

Hi my name is

Current output:

Hi
my
name
is

Desired output:

Hi(2)
my(2)
name(4)
is(2)

My current Code:

#include <stdio.h>

#define MAX 100

int main(void) {

    int c = 0;
    size_t n = 0;

    printf("\n Enter a sentence.\n\n input: ");

    /* read up to 100 characters from stdin, print each word on a line */
    while (n < MAX && (c = getchar()) != EOF && c != '\n')
    {
        if (c == ' ')
            printf("\n");
        else
            printf("%c", c);
        n++;
    }
    printf("\n");

    if (n == MAX) /* read and discard remaining chars in stdin */
        while ((c = getchar()) != '\n' && c != EOF);

    return 0;
}

How can I do that?

Answer 1

For completeness a different approach reading the whole input in one call and then tokenising it:

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

#define MAX (100)

int main(void) 
{
  int result = EXIT_SUCCESS; /* Be optimistic. */ 
  char s[MAX +1];

  printf("\n Enter a sentence.\n\n input: ");

  /* read up to 100 characters from stdin, print each word on a line */

  if (NULL == fgets(s, sizeof s, stdin))
  {
    if (ferror(stdin))
    {
      perror("fgets() failed");
      result = EXIT_FAILURE;
    }
  }
  else
  {
    s[strcspn(s, "\r\n")] = '\0'; /* chop off carriage return, line feed, if any */

    for (char * pc = strtok(s, " "); NULL != pc; pc = strtok(NULL, " "))
    {
      printf("%s (%zu)\n", pc, strlen(pc));
    }
  }

  return result;
}

As the read buffer is never explicitly used the following variation is possible as well:

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

#define MAX (100)

int main(void) 
{
  int result = EXIT_SUCCESS; /* Be optimistic. */ 

  printf("\n Enter a sentence.\n\n input: ");

  {
  /* read up to 100 characters from stdin, print each word on a line */    
    char * pc = fgets((char[MAX+1]), MAX+1, stdin);
    if (NULL == pc)
    {
      if (ferror(stdin))
      {
        perror("fgets() failed");
        result = EXIT_FAILURE;
      }
    }
    else
    {
      pc[strcspn(pc, "\r\n")] = '\0'; /* chop off carriage return, line feed, if any */

      for (pc = strtok(pc, " "); NULL != pc; pc = strtok(NULL, " "))
      {
        printf("%s (%zu)\n", pc, strlen(pc));
      }
    }
  }

  return result;
}

Answer 2

Have one more variable and print out when you hit space.

size_t len = 0;

/* read up to 100 characters from stdin, print each word on a line */
while (n < MAX && (c = getchar()) != EOF && c != '\n')
{
    if (c == ' ') {
        printf("(%u)\n", len);
        len = 0;
    }
    else {
        len++;
        printf("%c", c);
    }
    n++;
}

Answer 3

In addition to the good answer by @kiranBiradar , you may want to add an additional variable that allows you to track whether you are in-a-word reading characters or outside-a-word reading whitespace . (using a simple int value as a flag set to 1 (true) for in-word or 0 (false) not-in-word is all you need) This will allow you to ignore leading whitespace, multiple included whitespace, or trailing whitespace in your input, eg, if your input was similar to:

"   my       dog   has      fleas   and my   cat has   none  "

Unless you are keeping track of the state of your read, whether you are in-word / not-in-word , you will be outputting multiple occurrences of "(0)\n" each time a whitespace character is read. By keeping a flag of whether you are in / not-in a word and setting it zero when you encounter your first whitespace after being in-word reading non-whitespace characters allows you to only output the length once on the first whitespace encountered.

Additionally, conditioning your read on c != '\n' will skip outputting the length of the final word, unless you include additional code after you exit your read loop.

Also by including <ctype.h> you have the isspace() macro available to check for all whitespace (eg, space, tab, newline, backspace, vertical-tab , etc...) It greatly simplifies your conditional checks.

Putting it altogether you could do:

#include <stdio.h>
#include <ctype.h>      /* for isspace() */

int main (void) {

    int c = 0, in = 0, len = 0;             /* char, in/out flag, length */

    fputs ("enter text: ", stdout);         /* prompt for text */
    fflush (stdout);                        /* (optional), but recommended */

    while ((c = getchar()) != EOF) {        /* loop reading chars until EOF */
        if (isspace (c)) {                  /* if input is space */
            if (in) {                       /* check if in-word */
                printf ("(%d)\n", len);     /* output (len) */
                len = 0;                    /* reset len zero */
                in = 0;                     /* set in flag zero (false) */
            }
            if (c == '\n')                  /* if space is \n */
                break;                      /* break read loop */
        }
        else {  /* if not whitespace */
            putchar (c);                    /* output char */
            len++;                          /* increment length */
            in = 1;                         /* set in flag 1 (true) */
        }
    }
}

( note: there is no reason to limit your read to n < MAX unless you simply want to arbitrarily limit your read of characters to the first 100-characters. There is no array being filled or other storage being occupied by the character c (aside from it's one byte). You could read billions if your input contained them)

Example Use/Output

$ ./bin/getchar_word_len
enter text:      my       dog   has      fleas   and my   cat has   none
my(2)
dog(3)
has(3)
fleas(5)
and(3)
my(2)
cat(3)
has(3)
none(4)

Look over both answers and let either of us know if you have further questions. If you are confused by the logic, take out an 8.5x11 sheet of paper and work through the logic of the loop for each character starting at the beginning of your input. It will make sense by the time you work through the first word.

Answer 4

I was actually having this problem the other day and I figured out the problem with this solution

#include <stdio.h>

#define MAX 100

int main(void) {

    int c = 0;
    size_t n = 0;

    printf("\n Enter a sentence.\n\n input: ");

    /* you've been gnomed */
#include <stdio.h>

#define MAX 100

int main(void) {

    int c = 0;
    size_t n = 0;

    printf("\n Enter a sentence.\n\n input: ");

    /* read up to 100 characters from stdin, print each word on a line */
    while (n < MAX && (c = getchar()) != EOF && c != '\n')
    {
        if (c == ' ')
            printf("\n");
        else
            printf("%c", c);
        n++;
    }
    printf("\n");

    if (n == MAX) /* read and discard remaining chars in stdin */
        while ((c = getchar()) != '\n' && c != EOF);

    return 0;
}
    while (n < MAX && (c = getchar()) != EOF && c != '\n')
    {
        if (c == ' ')
            printf("\n");
        else
            printf("%c", c);
        n++;
    }
    printf("\n");

    if (n == MAX) /* read and discard remaining chars in stdin */
        while ((c = getchar()) != '\n' && c != EOF);

    return 0;
}