/*
 * Example of function with simple output parameters 
 * Figures 6.3, page 283, Hanly and Koffman, 5ed. 
 * 
 */

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

void separate(double num, char *signp, int *wholep, double *fracp);   

int main()
{
    double value;
    char sn; 
    int whl; 
    double fr; 

    printf("Please input the value = "); 
    scanf("%lf",&value); 

    separate(value, &sn, &whl, &fr);    /* the address of ...  */

    printf("Parts of %.4f \n",value); 
    printf("   sign                   : %c\n",sn); 
    printf("   whole number magnitude : %d\n",whl); 
    printf("   fractional parts       : %.4f\n",fr); 

    return  0; 
} 

/* ---------------------------------------------------------------- */  

/* Separate a number into three parts: 
 *  sign (+, -, or blank), a whole number magnitude, and a fractional part
 * 
 * Pre: num is defined; signp, wholep, fracp contain address of memory cells 
 *      where results are to be stored 
 * Post: results are stored in the cells pointed by signp, wholep, fracp
 */

void   
separate(double num, char *signp, int *wholep, double *fracp)  
{
    double magnitude;  

    if (num < 0)
        *signp = '-';
    else if (num == 0)
        *signp = ' ';
    else
        *signp = '+';

    magnitude = fabs(num);
    *wholep = floor(magnitude);
    *fracp = magnitude - *wholep;

    printf("\nwhat is *wholep = %d",*wholep); 
    printf("\nwhat is *fracp = %f",*fracp); 
}

// 
// Remarks: 
// 
// (1) char *signp,: 
//     signp will contain the address of a type char variable, 
//     or say "signp is a pointer to a type char variable" 
// 
// (2) int *wholep: 
//     wholep is a pointer to a type int variable. 
// 
// (3) double *fracp: 
//      fracp is a pointer to a type double variable. 
// 
// (4) no return statement, void!
// 
// (5) Three meanings of * symbol 
//     (a) multiplication, as binary operator 
//                    a*b, 
//     (b) ``pointer to'', in the declaration 
//     (c) unary indirection operator, ``follow the pointer', in function body
// 
// (6) pointer: a memory cell whose content is the address of another
//     memory cell.  
//