C pointers lessons from mycodeschool(up to video 7 not incl)

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <time.h>

int basicPointers()
{
    printf("\nbasicPointers\n");
    printf("----------------\n\n");
    int a = 8;
    int *P;
    P = &a;
    printf("The address of a is %d\n", P);
    printf("The value of Pointer P is %d\n", *P);
    printf("The address of a is %d\n", &a);
    printf("The value of a is %d\n", a);
    *P = 12;
    printf("The value of a after Pointer P changed its value is %d\n", a);
    int b = 20;
    *P = b;
    printf("The value of Pointer P is %d\n", *P);
    printf("The value of a is %d\n", a);
    printf("The address of a is %d\n", P);
    printf("The Value of b is %d\n", b);
    return 0;
}

int arithmaticPointers(){
    int a = 10;
    int *p;
    p = &a;
    printf("\narithmaticPointers\n");
    printf("---------------------\n\n");
    printf("Address of p is %d\n",p);
    printf("value of p is %d\n",*p);
    printf("size of integer is %d bytes\n", sizeof(int));
    printf("Address p+1 is %d\n",p+1);
    printf("value at address p+1 is %d\n",*(p+1)); //Gives unwanted behavior.

    return 0;
}
int pointers2Pointers(){
    printf("\npointers2Pointers\n");
    printf("-----------------\n\n");
    int x = 5;
    int* p = &x;
    *p = 6;
    int** q = &p;
    int*** r = &q;
    printf("This is the value of x: %d\n",x);
    printf("This is the value of x by using pointer p to retrieve the value of:%d\n", *p);
    printf("This is the value of x, by using the reference of **q, which uses the reference\nof p first, then p uses it's reference to retrieve the value of:%d\n", **q);
    printf("This is the value of q, by using the * reference of r to retrieve it's empty value of:%d\n", *r);
    printf("This is the value of p, by using the ** reference of r to retrieve it's empty value of:%d\n", **r);
    printf("This is the the value of x, by using the *** reference of r, it references q first, then p, uses it's reference to x to retrieve the value of:%d\n", ***r);

    ***r = 10; //We changed the value of x to 10 by using ***r
    **q = *p+2; //Changing the value of x to 10 + 2 by using **q
    printf("x = %d\n", x); //Should print 12
    return 0;
}
void pointerfunctionIncrement(int *p){ //*p is the value of the int at address a
    *p = (*p) + 1;
}

int pointerIncrement(){
    printf("\npointerIncrement\n");
    printf("-----------------\n\n");
    int a;
    a = 12;
    pointerfunctionIncrement(&a); //Address of a.
    printf("a = %d\n", a);
}

int pointersArrays(){
    printf("\npointersArrays\n");
    printf("-----------------\n\n");
    int a[] = {2,4,6,8,10};
    int i;
    int *p = a;
    for(i=0;i<5;i++){
        printf("The value of a[i] is: %d\n", a[i]);
        printf("The address of a[i] is: %d\n", &p[i]);
    }
    return 0;
}
int main(){
    basicPointers();
    arithmaticPointers();
    pointers2Pointers();
    pointerIncrement();
    pointersArrays();
    return 0;
}