Thread: How to add and delete items in a structure?

Originally Posted by JorgeChemE

Jim, I know how to use fgets but we are required to submit this project to be evaluated, in class we only studied scanf and gets for this purpose, we also studied getch, getchar, getche, puts and maybe something more I almost forget. The code I am using is the one the instructor expects according to what we are learning, otherwise, she would think we are cheating.

This isn't cheating. This is C in the year of 2017!
getch() was in the standard of 89/90, was deprecated in the standard of 99 and is no longer part of the standard from 2011.
Your instructor should learn that the programing language C is under a development process, like all other languages.
There is no advantage if student learn old and outdated practices. Rather, we have in the future programs with buffer overflow and undefined behavor and when we look why this happens, the programer from tomorrow will say: 'we have learn it this way'.
I mean, all instructors should look at the last standard and all schoolbooks should be updated to reflect the new standard.
The instructor can show you the old functions, but only that students know it and this functions can be in old code.
New code should allways be written to be accordant to the new standard.


Also, please consider what we have told you:
avoid global variables, hold the scope of variables as small as possible
avoid magic numbers, instead use #define
don't use fflush() on an input stream
don't use deprecated or outdated functions, instead use the new and safer functions


I think other members of this forum will complete this list, because i am a self learning hobbyist and not a full trained programer.

Originally Posted by christop

I think you meant gets() rather than getch(), as the latter never was part of any C standard (it comes from the DOS world, AFAIK).

Ooops, yes, i mean gets, sorry.

@JorgeChemE

Your search will never end.
Here is a skeleton that should work.

Code:

#define NAME_MAX 100

void modificar_mascota() {
    char nombre_mascota[NAME_MAX];
    tmascota *temp;

    if (primero == NULL) return; // check if we have a valid pointer

    printf("\nIntroduzca el nombre de la mascota a modificar: ");
    fflush(stdout);
    fgets(nombre_mascota, NAME_MAX, stdin);

    temp = primero;
    while (temp) { // same as 'temp != NULL'
        if (strcmp(temp->nombre_mascota, nombre_mascota) == 0) break;
        temp=temp->siguiente;
    }

    if (temp) {
        // edit the pet where 'temp' points to
    }
    else {
        printf("Sorry, no pet found\n");
    }
}

You don't need to allocate memory for a new struct, because you want to edit one.
The while-loop will break if the pet was found, otherwise it runs until there is no more pets in the list and temp become NULL.
But this is a quick and dirty solution, because if the name of the pet is 'Charly' and you enter 'charly', the pet will not be found (case sensitive).

PS: this code is untested, i have it written out of my head.