Dereference

Dereferencing a pointer reads or writes the object at the stored address.

dereference.c

#include <stdio.h>

int main(void) {
    int value = ;
    int *ptr = &value;

    *ptr = *ptr + 2;

    printf("value=%d\n", value);
    return 0;
}

#include <stdio.h>

int main(void) {
    int value = ;
    int *ptr = &value;

    *ptr = *ptr + 2;

    printf("value=%d\n", value);
    return 0;
}

#include <stdio.h>

int main(void) {
    int value = ;
    int *ptr = &value;

    *ptr = *ptr + 2;

    printf("value=%d\n", value);
    return 0;
}

dereference `*ptr` means the object pointed to by `ptr`.

write through pointer Assigning to `*ptr` updates the original variable.