Error Using pointers to get memory address locations

Question

I have since figured this out. Thank you...I'm new to C and having trouble getting the memory address of the variable that's assigned to the pointer.

What am I missing or not understanding here. The valueVariable needs to be declared. The pointerVariable needs to be declared and set to the &valueVariable. still unsure what %x does to be honest. TIA

int main () {

    double innerD, outerD, density, thickness;
    double *innerDPointer, *outerDPointer, *thicknessPointer, *densityPointer;

    innerD = 0.0;
    outerD = 0.0;
    density = 0.0;
    thickness = 0.0;

    innerDPointer = &innerD;
    outerDPointer = &outerD;
    densityPointer = &density;
    thicknessPointer = &thickness;

    int quantity;
    int *quantityPointer;

    quantityPointer = &quantity;

    printf("\nAddress of innerD variable: %x\n", &innerD);
    printf("\nAddress of outerD variable: %x\n", &outerD);
    printf("\nAddress of density variable: %x\n", &density);
    printf("\nAddress of thickness variable: %x\n", &thickness);
    printf("\nAddress of quantity variable: %x\n", &quantity);

    return 0;
}