how not to count spaces while counting the length of string in c

Question

I am using the following code it is counting the spaces in the string but i don't want to count spaces.

#include<stdio.h>
#include<conio.h>

void main()
{
   char*ptr,str[30];
   int size=0;
   int word=0;

   puts("enter the string");
   gets(str);
   fflush(stdin);

   for(ptr=str;*ptr!='\0',ptr++)
   {
       size++;
   }

   printf("size of string is = %d",size);
   getchar();
}

Is this how you write your code? No new lines, no spaces, nothing? — Kiril Kirov, Jun 10 '15 at 07:24
`void main` is not standard c. Are you using a non-standard compiler? — eerorika, Jun 10 '15 at 07:26
Rewrite `size++;` to `if(some_condition_to_check_if_ptr_is_not_space) size++;`. Now it is up to you find what `some_condition_to_check_if_ptr_is_not_space` is? — Mohit Jain, Jun 10 '15 at 07:26
Sharing your research helps everyone. Tell us what you've tried and why it didn’t meet your needs. This demonstrates that you’ve taken the time to try to help yourself, it saves us from reiterating obvious answers, and most of all it helps you get a more specific and relevant answer! Also see [how to ask](http://stackoverflow.com/questions/how-to-ask) — Eregrith, Jun 10 '15 at 07:27
Not related to your problem, but NEVER EVER USE gets, IT IS DANGEROUSLY UNSAFE. Use fgets(str, sizeof(str), stdin) instead. And drop that fflush(stdin), it is undefined behavior (https://stackoverflow.com/a/2979217/311635). — Rudi, Jun 10 '15 at 07:33

Sourav Ghosh · Answer 1 · 2015-06-10T07:33:06.933

5

TL;DR; answer : Skip the counter (size) increment, when the value (at that pointer location) is a space.

Please write the code yourself and update us about the result.

That said, IMHO, first you should notice (and correct) a few things, as

void main() is not standard. Use int main(void) instead.
Never use gets().It suffers seriously from buffer overflow issues. Use fgets() instead.
fflush(stdin) is undefined behaviour. Get rid of it ASAP.

edited Jun 10 '15 at 07:33

answered Jun 10 '15 at 07:27

Sourav Ghosh

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Only answer that mentions the evilness of `gets` - +1 – user4520 Jun 10 '15 at 07:32
1

@szczurcio and `fflush(stdin)` also, for that matter. :-) – Sourav Ghosh Jun 10 '15 at 07:33

Arial · Answer 2 · 2015-06-10T07:50:26.770

0

Try the following codes using pointer arithmetics instead:

while (*ptr) {
    if (*ptr != ' ') {
        size++;
    }
}

This will loop through the characters until it hit a null terminator '\0', and increment as necessary.

edited Jun 10 '15 at 07:50

answered Jun 10 '15 at 07:29

Arial

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this is rather overkill for the problem at hand. Given he already has a loop that iterates all characters. Much simpler to just skip spaces inside the counting loop. – DrKoch Jun 10 '15 at 07:31
Very good point. Looping over the characters and ignoring the space is a much efficient way to solve this problem and gives O(n). I'll change my answer. :) – Arial Jun 10 '15 at 07:45

Guillaume Munsch · Answer 3 · 2015-06-10T07:45:15.177

0

Try this

int my_strlen(char *str)
{
int i, j = 0;
while (str[i] != '\0')
{
   if (str[i] != ' ')
       ++j;
   ++i;
}
return j;
}

edited Jun 10 '15 at 07:45

answered Jun 10 '15 at 07:30

Guillaume Munsch

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Another spoiler. Keeps OP from learning. Fortunately your code has a bug, so OP needs to learn even more - good. – DrKoch Jun 10 '15 at 07:32

score 0 · Answer 4 · answered Jun 10 '15 at 07:31

0

Inside your loop:

skip spaces

count all other characters

answered Jun 10 '15 at 07:31

DrKoch

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how not to count spaces while counting the length of string in c

4 Answers4