Ecrire une fonction qui intervertit deux int * en c et également écrire appel à cette fonction

Question

Une belle question interview C:

Pouvez-vous écrire une fonction qui intervertit deux int * en C et écrire aussi un appel à ce fonction?

int a = 10, b = 20; 
int* first_pointer = &a; 
int* second_pointer = &b; 
/* Below line should print (*first_pointer) = 10, (*second_pointer) = 20 */ 
printf("(*first_pointer) = %d, (*second_pointer) = %d\n",*first_pointer, *second_pointer); 
/// **** Call your swap function here **** 
/* Below line should print (*first_pointer) = 20, (*second_pointer) = 10 */ 
printf("(*first_pointer) = %d, (*second_pointer) = %d\n",*first_pointer, *second_pointer); 

Answer 1

Fonction est ici,

void swap(int** first_pointer, int **second_pointer) 
{ 
    int *temp = *first_pointer; 
    *first_pointer = *second_pointer; 
    *second_pointer = temp; 
} 

appel de fonction

est ici,

int a = 10, b = 20; 
int* first_pointer = &a; 
int* second_pointer = &b; 
// Below will print (*first_pointer) = 10, (*second_pointer) = 20 
printf("(*first_pointer) = %d, (*second_pointer) = %d\n",*first_pointer, *second_pointer); 
swap(&first_pointer, &second_pointer); 
// Below will print (*first_pointer) = 20, (*second_pointer) = 10 
printf("(*first_pointer) = %d, (*second_pointer) = %d\n",*first_pointer, *second_pointer);