//////////////////////////
//
// prog_practice_6 project
//
// 9/19/22  tj
//
// practice pointers with functions
//
////////////////////////////
#include "mbed.h"
#include <stdio.h>

void splash(void);
void read_vals(int* val1, int* val2);
float swap_ave(int* v1, int* v2);
void calc_ave(int v1, int v2, float * result);
float * point_2x(float * ref);

int main(void){ 
    setbuf(stdout, NULL);   // fix buffer problem

    // splash
    splash();

    int a;
    int b;
    float c;
    float * d_ptr;
  
    // show garbage
    printf("%i %i %f %p %p %p\n", a, b, c, &a, &b, &c);

    // read in 2 numbers with scanf
    printf("please enter 2 ints: ");
    scanf("%i %i", &a, &b);
    printf("%i %i %f %p %p %p\n", a, b, c, &a, &b, &c);

    // read in 2 numbers from our own function
    read_vals(&a, &b);
    printf("%i %i %f %p %p %p\n", a, b, c, &a, &b, &c);

    // swap values AND provide the ave
    c = swap_ave(&a, &b);
    printf("%i %i %f\n", a, b, c);

    // cal ave using calc_ave
    calc_ave(a, b, &c);
    printf("%i %i %f\n", a, b, c);

    // show that we can return a pointer
    // we could have just said d_ptr = &c 
    // we will not return pointers in this class
    d_ptr = point_2x(&c);
    printf("%f %p %f\n", c, d_ptr, *d_ptr);

    return 0;
}// end main

void splash(void){
    // print splash message
    printf("\n\nPractice using pointers in functions\n\n");

    return;
}// end splash

void read_vals(int* val1, int* val2){
    printf("\nEntered read_vals\n");
    printf("val1, val2: %p %p\n", val1, val2);
    
    // read in 2 values and store via address reference
    // note: scanf is already expecting addresses(pointers) so you
    // can use val1 and val2 directly in the scanf function
    printf("please enter an integer value: ");
    scanf("%i", val1);
    printf("please enter an integer value: ");
    scanf("%i", val2);
    
    return;
}// end read_vals

float swap_ave(int* v1, int* v2){
    printf("\nEntered swap_ave\n");
    printf("v1, v2: %p %p\n", v1, v2);

    // swap two values and calculate/return the average
    int tmp;
    tmp = *v1;
    *v1 = *v2;
    *v2 = tmp;

    return ((*v1 + *v2)/2.0);
}// end swap_ave

void calc_ave(int v1, int v2, float * result){
    printf("\nEntered calc_ave\n");
    printf("v1, v2, result: %i %i %p\n", v1, v2, result);

    // calculate the average
    *result = (v1 + v2)/2.0;

    return;
}// end calc_ave

float * point_2x(float * ref){
    //return the pointer passed to the function

    return ref;
}// end point_2x