Challenge

Objective-C Programming (2nd Edition) 10. Pass-By-Reference
1

File: main.c

[code]#include <stdio.h>
#include <math.h>

void metersToFeetAndInches(double meters, unsigned int *ftPtr, double *inPtr)
{
// This function assumes meters is non-negative.

// Convert the number of meters into a floating-point number of feet
double rawFeet = meters * 3.281; // e.g 2.4536

// How many complete feet as an unsigned int?
// unsigned int feet = (unsigned int)floor(rawFeet);
double feet;
double fractionalFoot = modf(rawFeet, &feet);

// Store the number of feet at the supplied address
if (ftPtr) {
    printf("Storing %.0f to the address %p\n", feet, ftPtr);
    *ftPtr = feet;
}

// Calculate inches
// double fractionalFoot = rawFeet - feet;
double inches = fractionalFoot * 12.0;

// Store the number of inches at the supplied address
if (inPtr) {
    printf("Storing %.2f to the address %p\n", inches, inPtr);
    *inPtr = inches;
}

}

int main(int argc, const char * argv[])
{
/*
double pi = 3.14;
double integerPart;
double fractionPart;

// Pass the address of integerPart as an argument
fractionPart = modf(pi, &integerPart);

// Find the value stored in integerPart
printf("integerPart = %.0f, fractionPart = %.2f\n", integerPart, fractionPart);
*/

double meters = 3.0;
unsigned int feet;
double inches;

metersToFeetAndInches(meters, &feet, &inches);
printf("%.1f meters is equal to %d feet and %.1f inches\n", meters, feet, inches);

return 0;

}[/code]
Output:
Storing 9 to the address 0x7fff5fbff914
Storing 10.12 to the address 0x7fff5fbff908
3.0 meters is equal to 9 feet and 10.1 inches
Program ended with exit code: 0