Warning: Assignment from incompatible pointer type

[plazzasele]

I want to register a new Person by using the set and get method.
I am running my code on a program ( DEVc++), and when i compile the code i get this error message:

[Warning] assignment from incompatible pointer type.

#include <stdlib.h>
#include <stdio.h>
 
struct Person {
       char *name;
 
       void (*setName) (struct Person *this, char *name); 
       char (*getName) (struct Person *this);
       };
 
void Person_setName (struct Person *this, char* name) {
    this->name = name;
}
 
char *Person_getNavn (struct Person *this) {
    return this->name;
}
 
void menu();
void regPerson();
 
 
int main(char *argv[], int argc) {
    menu();
    return 0;
}
 
void menu() {
    int c = -1;
    while (c != 0) {
        printf("\n==========\n");
        printf("Main Menu:\n");
        printf("==========\n");
        printf("0 - Exit\n");
        printf("1 - Register new person\n");
 
        printf("Choice: ");
        scanf("%i", &c);
        printf("\n");
 
switch (c) {
            case 0:
                printf("\nGoodbye\n");
                return;
            case 1:
                regPerson();
                break;
                        default:
                printf("Unrecognized choice, please try again.\n");
        }
    }
}
 
void regPerson() {
    struct Person *p=(struct Person *)malloc(sizeof(struct Person *));
 
    char *name = (char *)malloc(sizeof(char) * 100);
    char *id = (char *)malloc(sizeof(char) * 100);
 
    p->setName=Person_setName;
    p->getName=Person_getName;  // it is here i get an error.
 
 
    printf("===============\n");
    printf("Register person\n");
    printf("===============\n");
    printf("Name: ");
    scanf("%s", name);
    printf("ID: ");
    scanf("%s", id);
 
    p->navn=(name);
    p->id=(id);
    printf("\n Navn: %s\n Id: %s ", p->navn,p->id);
 
}

[newb16]

You have a typo(?) in Person_getNavn() name, it may be the reason. If not, they also differ by return type - char and char*.

[plazzasele]

hi..

sorry that is a mistake.. in line 72 there should be p->name(name); not p->navn(name);

and what do you mean by typo(?) ..??
and how to return a char* .??

[plazzasele]

@newb16
i was working on this code, this what i come to. now i dont get anymore error while compiling, but the program stopes when it comes to this line:
printf("navn: %s\n",p->getNavn(p));
have i wright the rest wright..??

#include <stdlib.h>
#include <stdio.h>
 
struct Person{
       char *name;
       char *id;
       void (*setName)(struct Person *this, char *name);
       char (*getName)(struct Person *this);
       void (*setId)(struct Person *this, char *id);
       char (*getId)(struct Person *this);
       };
void Person_setName(struct Person *this, char *name) {
    this->name = name;
}
 
char Person_getName(struct Person *this) {
    return *this->name;
}
void Person_setId(struct Person *this, char *id) {
    this->id = id;
}
 
char Person_getId(struct Person *this) {
    return *this->id;
}
void menu();
void regPerson();
 
int main(char *argv[], int argc) {
    menu();
    return 0;
}
 
void menu() {
    int c = -1;
    while (c != 0) {
        printf("\n==========\n");
        printf("Main Menu:\n");
        printf("==========\n");
        printf("0 - Exit\n");
        printf("1 - Register new person\n");
        printf("Choice: ");
        scanf("%i", &c);
 
        switch (c) {
            case 0:
                printf("\nGoodbye\n");
                return;
            case 1:
                regPerson();
                break;
default:
                printf("Unrecognized choice, please try again.\n");
        }
    }
}
 
void regPerson() {
    struct Person *p=(struct Person *)malloc(sizeof(struct Person *));
 
    char *name = (char *)malloc(sizeof(char) * 100);
    char *id = (char *)malloc(sizeof(char) * 100);
 
    p->name=(char *)malloc(sizeof(char) * 100);
    p->id=(char *)malloc(sizeof(char) * 100);
 
    p->setName=(*Person_setName);
    p->getName=*Person_getName;
    p->setId=*Person_setId;
    p->getId=*Person_getId;
    printf("===============\n");
    printf("Register person\n");
    printf("===============\n");
    printf("Name: ");
    scanf("%s", name);
    printf("ID: ");
    scanf("%s", id);
    printf("\nName: %s\n Id: %s\n",name,id);
 
    p->setName(p,&*name);
 
    p->setId(p,&*id);
    printf("test\n");
 
    printf("name: %s\n",p->getNavn(p));
 
    printf("id: %s\n",p->getId);
 
 
}

[newb16]

I don't know how you managed to compile it, because you still declare it as getName in the structure declaration and call as getNavn.
Then, char (*getName)(struct Person *this);
returns char , not char*. And printf %s format specifier expects char*, but your function returns char. It can't check the type mismatch, but crashes instead.
change it to char* (*getName)(struct Person *this); and change Person_getName accordingly.
You getId() is also wrong.

[plazzasele]

@newb16
thank you very much newb16..

now it is working.. and i am sorry again for the mistakes.. Navn suppose to be name..