This program as you can see is kind of "Student Management System". I couldn't divide my code into 2 c files as "main.c" and "process.c". I need to process the data in the "process.s" and run the code by makefile. Can anyone give me a hint how to divide them and how to create a header file for them. I left main() in the main.c and put everything else in the process.c. In the header file of main.h, I initialized the functions and struct, but it seems to be incorrect.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
struct Person{
    char name[20];
    char phone[15];
    struct Person* next;
}* head;

void Enroll(char* name, char* phone){
    struct Person* person = (struct Person*) malloc(sizeof(struct Person));
    strcpy(person->name, name);
    strcpy(person->phone, phone);
    person->next = NULL;

    if (head == NULL){
            head = person;
    }else{
            person->next = head;
            head = person;
    }
}

void List(){
    struct Person* temp = head;
    printf("---List---");
    while(temp =! NULL){
            printf("%s      %s", temp->name, temp->phone);
            temp = temp->next;
    }
}

void Search(char* name){
    struct Person* temp = head;
    while(temp != NULL){
            if (strcpy(temp->name, name) != 0){
                    printf("%s      %s", temp->name, temp->phone);
                    return;
            }
            temp = temp->next;
    }
    printf("%s Could not find\n", name);
}


void Delete(char* name){
    struct Student* temp1 = head;
    struct Student* temp2 = head;
    while(temp1 != NULL){
            if (strcpy(temp1->name, name) != 0){
                    if (temp1 == temp2){
                            head = head->next;
                            free(temp1);
                    }else{
                            temp2->next = temp1->next;
                            free(temp1);
                    }
                    printf("%s Delete Success", name);
                    return;
            }
            temp2 = temp1;
            temp1 = temp1->next;
    }
    printf("%s Could not find", name);
}

int main(){
    head = NULL;
    char name[20];
    char phone[15];
    int select;

    printf("Welcome to the Enrollment Management System!\n");
    printf("[1] Enroll      [2] List        [3] Search      [4] Delete      [5]Quit\nSelection: ");
    scanf("%d", &select);
    while(select != 5){
            if (select == 1){
                    printf("Name: ");
                    scanf("%s", name);
                    printf("Phone: ");
                    scanf("%s", phone);
                    Enroll(name, phone);
            }
            if (select == 2){
                    List();
            }
            if (select == 3){
                    printf("Name: ");
                    scanf("%s", name);
                    Search(name);
            }
            if (select == 4){
                    printf("Name: ");
                    scanf("%s", name);
                    Delete(name);
            }
    }
}

CodePudding user response：

You could create a header ".h" file on the same directory and you could add the instruction on the top of the main.c like #include "mylib.h"

If the header file is included with <>, the compiler will search a determined directory path of header files, if the header file is included with the "" compiler will look in the same directory as the main.c file.

CodePudding user response：

The answer posted by Ugur A is correct. When your compiler preprocesses your c file, it normally just merges all the code of the .h to the c file, replacing the #include statement with it. So that's how it happens.

In addition to that, if you wanted to split your code into two c files, you can do it like-

foo.c:

int foo() {
    // do something
}

foobar.c:

int foo();

int main() {
    foo();
}

Particularly, you'd have to declare all the functions in your file containing main().

And when compiling-

gcc foo.c foobar.c