Building an own strlen_function as an exercise

Hi!

Code:

---

#include <stdio.h>

int stringlen(char* field, int length) {
    int i = 0;


    while(field[i] != '\0') {
        i++;
    }


    return i;
}


int main() {
    char text[100] = "Hello";


    /* #define LAENGE 100


    char array[LAENGE];


    fgets(array, LAENGE, stdin);
    */


    int laenge;
    laenge = stringlen(text, 100);


    printf("%d\n", laenge);


        return 0;
}

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If I would "uncomment" my commented out code and out-comment the used code in the main(), basically if I would use fgets for a string_userinput, then regards to my function the length (would not be "i", but "i - 1". Why is this?
Has it something with "stdin" to do?

fgets() always put a NUL char at the end of the buffer.

Quote:

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Originally Posted by flp1969

fgets() always put a NUL char at the end of the buffer.

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ah ok,
but with NUL char yoou do not mean '\0', since '\0' is also existing within every char-array at the end and hence also within
every initialized string?

may i ask why you have a length parameter for your function

don't quote me on this but i think what's happening if you use the commented out code is you get a char array of 99 characters and the hundredth is the \0 character i only say this as i wanted to read in a single number using fgets and needed a buffer size of 2. this could be why i is 99 not 100.

Your function seems to work correctly (though as cooper1200 asked, why does it take a length parameter?):

Code:

---

c@c:~$ cat 177566.c
#include <stdio.h>

int stringlen(char* field, int length) {
    int i = 0;


    while(field[i] != '\0') {
        i++;
    }


    return i;
}


int main() {
    char text[100] = "Hello";


    #define LAENGE 100


    char array[LAENGE];


    fgets(array, LAENGE, stdin);


    int laenge;
    laenge = stringlen(array, 100);


    printf("%d\n", laenge);


        return 0;
}
c@c:~$ ./177566
Hello
6
c@c:~$

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Remember that fgets() leaves the newline ('\n') character at the end of the string. That is counted in the string's length.

Quote:

---

Originally Posted by cooper1200

may i ask why you have a length parameter for your function

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Just practice - has no other purpose.

Quote:

---

Originally Posted by christop

Your function seems to work correctly (though as cooper1200 asked, why does it take a length parameter?):

Code:

---

c@c:~$ cat 177566.c
#include <stdio.h>

int stringlen(char* field, int length) {
    int i = 0;


    while(field[i] != '\0') {
        i++;
    }


    return i;
}


int main() {
    char text[100] = "Hello";


    #define LAENGE 100


    char array[LAENGE];


    fgets(array, LAENGE, stdin);


    int laenge;
    laenge = stringlen(array, 100);


    printf("%d\n", laenge);


        return 0;
}
c@c:~$ ./177566
Hello
6
c@c:~$

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Remember that fgets() leaves the newline ('\n') character at the end of the string. That is counted in the string's length.

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ah ok, thanks^^