Write a module list.c that implements the interface with an associated Makefile. Your module should hide the list of cars internally with the global declaration:
static car_t *front=NULL;
header file:
#pragma once
/*
* list.h -- public interface to a list of cars
*/
#include <stdint.h>
#define MAXREG 10
/* the representation of a car */
typedef struct car {
struct car *next;
char plate[MAXREG];
double price;
int year;
} car_t;
/* put(): place a car at the beginning of the list
* returns 0 if successful; nonzero otherwise
*/
int32_t lput(car_t *cp);
/* get(): remove and return the first car in the list;
* return NULL if the list is empty
*/
car_t *lget();
/* apply a function to every car in the list */
void lapply(void (*fn)(car_t *cp));
/* remove(): find, remove, and return any car with
* the designated plate; return NULL if not present
*/
car_t *lremove(char *platep);
To implement the list.c module, you need to follow these steps:
Step 1: Create a new file called list.c and open it in a text editor.
Step 2: Include the necessary header files at the top of the file:
```c
#include "list.h"
#include <stdlib.h>
#include <string.h>
```
Step 3: Define the private global variable `car_t *front=NULL;` inside the list.c file outside of any function. This variable will be used to keep track of the first car in the list.
```c
static car_t *front = NULL;
```
Step 4: Implement the `lput(car_t *cp)` function. This function should add a car to the beginning of the list.
```c
int32_t lput(car_t *cp) {
if (cp == NULL)
return -1; // Error: Invalid car pointer
cp->next = front;
front = cp;
return 0; // Success
}
```
Step 5: Implement the `lget()` function. This function should remove and return the first car in the list.
```c
car_t *lget() {
if (front == NULL)
return NULL; // List is empty
car_t *firstCar = front;
front = front->next;
firstCar->next = NULL;
return firstCar;
}
```
Step 6: Implement the `lapply(void (*fn)(car_t *cp))` function. This function should apply a given function to every car in the list.
```c
void lapply(void (*fn)(car_t *cp)) {
car_t *current = front;
while (current != NULL) {
fn(current);
current = current->next;
}
}
```
Step 7: Implement the `lremove(char *platep)` function. This function should find, remove, and return any car with the designated plate.
```c
car_t *lremove(char *platep) {
if (platep == NULL)
return NULL; // Error: Invalid plate pointer
car_t *current = front;
car_t *previous = NULL;
while (current != NULL) {
if (strcmp(current->plate, platep) == 0) {
if (previous != NULL)
previous->next = current->next;
else
front = current->next;
current->next = NULL;
return current;
}
previous = current;
current = current->next;
}
return NULL; // Car with the given plate was not found
}
```
Step 8: Save and close the list.c file.
To create the associated Makefile, you need to follow these steps:
Step 1: Create a new file called Makefile and open it in a text editor.
Step 2: Add the following contents to the Makefile:
```
CC=gcc
CFLAGS=-Wall -Wextra
list.o: list.c
$(CC) $(CFLAGS) -c list.c
clean:
rm -f *.o
.PHONY: clean
```
Step 3: Save and close the Makefile.
You can now use the list.c module and the associated Makefile in your project by including the "list.h" header file and compiling the list.c file using the Makefile.