Databases
StackOverflow2013
Postsdbo
POWhy is fgets() and strncmp() not working in this C code for string comparison?
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POWhy is fgets() and strncmp() not working in this C code for string comparison?
    primarykey
    data
    text
    <p>This is a very fun problem I am running into. I did a lot of searching on stack overflow and found others had some similar problems. So I wrote my code accordingly. I originally had <code>fscan()</code> and <code>strcmp()</code>, but that completely bombed on me. So other posts suggested <code>fgets()</code> and <code>strncmp()</code> and using the length to compare them. </p> <p>I tried to debug what I was doing by printing out the size of my two strings. I thought, maybe they have <code>/n</code> floating in there or something and messing it up (another post talked about that, but I don't think that is happening here). So if the size is the same, the limit for <code>strncmp()</code> should be the same. Right? Just to make sure they are supposedly being compared right. Now, I know that if the strings are the same, it returns <code>0</code> otherwise a negative with <code>strncmp()</code>. But it's not working. </p> <p>Here is the output I am getting: </p> <pre><code>perk repk Enter your guess: perk Word size: 8 and Guess size: 8 Your guess is wrong Enter your guess: </code></pre> <p>Here is my code:</p> <pre><code>void guess(char *word, char *jumbleWord) { size_t wordLen = strlen(word); size_t guessLen; printf("word is: %s\n",word); printf("jumble is: %s\n", jumbleWord); char *guess = malloc(sizeof(char) * (MAX_WORD_LENGTH + 1)); do { printf("Enter your guess: "); fgets(guess, MAX_WORD_LENGTH, stdin); printf("\nword: -%s- and guess: -%s-", word, guess); guessLen = strlen(guess); //int size1 = strlen(word); //int size2 = strlen(guess); //printf("Word size: %d and Guess size: %d\n",size1,size2); if(strncmp(guess,word,wordLen) == 0) { printf("Your guess is correct\n"); break; } }while(1); } </code></pre> <p>I updated it from suggestions below. Especially after learning the difference between <code>char *</code> as a pointer and referring to something as a <em>string</em>. However, it's still giving me the same error. </p> <p>Please note that <code>MAX_WORD_LENGTH</code> is a define statement used at the top of my program as </p> <pre><code>#define MAX_WORD_LENGTH 25 </code></pre>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USGeekyOmega
    1. USGeekyOmega
    plurals
    1. PL
      singulars
      1. LTLinked
    1. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    3. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POWhy is fgets() and strncmp() not working in this C code for string comparison?
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POWhy is fgets() and strncmp() not working in this C code for string comparison?
      1. This table or related slice is empty.
      1. VTUpMod
    1. COI put in something called *jumbleword. Don't worry about it. I use it later, but omit it to the nuts and bolts for my problem here.
      singulars
      1. POWhy is fgets() and strncmp() not working in this C code for string comparison?
      1. USGeekyOmega
    2. CO+1 for nice question formulation ;) but you should use `strlen` instead of `sizeof`, sizeof returns only size of type or fixed length structure.
      singulars
      1. POWhy is fgets() and strncmp() not working in this C code for string comparison?
      1. USVyktor
    3. COfgets reads a line, so your `guess` buffer will contain a `\n` character. How does the word you're comparing against look like, where does it come from ? Does it contain a newline ? (You could print it out with printf("Comparing '%s' and '%s'\n", word, guess); That way you'll see if there's some whitespace or junk inbetween the apostrophes.
      singulars
      1. POWhy is fgets() and strncmp() not working in this C code for string comparison?
      1. USnos
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload