Urgent help in finding the length

This is a discussion on Urgent help in finding the length within the C Programming forums, part of the General Programming Boards category; Hello all, I need help with finding the length of the string input by the user. It prints out 100 ...

  1. #1
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    Urgent help in finding the length

    Hello all,

    I need help with finding the length of the string input by the user.

    It prints out 100 each time.

    Also i cannot use the strlen function

    Also is there a way that each of those strings can be converted to single characters? like each of s can be assigned to a char?

    Thank You for ur help...

    Code:
    #include <stdio.h>
    
    #define MAX 100
    
    int main( int argc, char *argv[]) {
        char s[MAX];
        int i, j=0;
    //    char c;
    
        printf("Enter a string\n");
        fgets(s, MAX, stdin);
    
        for(i =0; i<MAX; i++ ) {
           s[MAX] = j;
           j++;
        }
    
        printf("The repetition of this line is:");
        puts(s);
    
        printf("The length is %d.\n", j);
        return 0;
    
    }
    Last edited by s.sidak; 10-31-2010 at 08:55 PM.

  2. #2
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    look up strlen()....

  3. #3
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    Sorry, I cannot use strlen

    Is there any other way to find the length without the strlen function?


    Thanks

  4. #4
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    You can't use strlen() ... why not? It's a standard C library function...

    I suppose you could write your own version. All strlen() does is loop through a string looking for the null character at the end. Should be easy enough to duplicate...
    Code:
    #include <stdio.h>
    
    #define MAX 100
    
    int main( int argc, char *argv[]) {
        char s[MAX];
        int i, j=0;
    //    char c;
    
        printf("Enter a string\n");
        fgets(s, MAX, stdin);
    
        for(i =0; i<MAX; i++ ) {
          if (s[i] == null)     // exit when null found
            { j =  i;
               break; }
        }
    
        j = (j == 0) ? Max : j;  // return MAX if no null
    
        printf("The repetition of this line is:");
        puts(s);
    
        printf("The length is %d.\n", j);
        return 0; }
    Last edited by CommonTater; 10-31-2010 at 09:18 PM.

  5. #5
    Code Goddess Prelude's Avatar
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    >Is there any other way to find the length without the strlen function?
    The entirety of the standard library can be written in C, so it stands to reason that if you can't use strlen, you can write your own function that does exactly the same thing:
    Code:
    size_t my_strlen(const char *s)
    {
        size_t n = 0;
    
        while (*s != '\0') {
            ++n;
            ++s;
        }
    
        return n;
    }
    >You can't use strlen() ... why not? It's a standard C library function...
    Obviously because the OP's teacher is one who favors stupid restrictions as a teaching style. It's much easier than putting forth the effort of coming up with practical problems.

    >if (s[i] == null) // exit when null found
    What's null? I can only assume you meant NULL, but keep in mind that NULL shouldn't be used in place of '\0'. It's strictly meant for use in the context of a pointer.
    Code:
    for(i =0; i<MAX; i++ ) {
          if (s[i] == null)     // exit when null found
            { j =  i;
               break; }
        }
    
        j = (j == 0) ? Max : j;  // return MAX if no null
    This is a very awkward algorithm. j isn't needed at all because the loop will stop when i reaches MAX. You could simply assign i to j after the loop, or use i directly:
    Code:
    for (i = 0; i < MAX; i++) {
        if (s[i] == '\0')
            break;
    }
    
    /* i == MAX || s[i] == '\0' */
    My best code is written with the delete key.

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