This is a c programming question on pointer

Question

Write a function that will take the length, width and height of a box, and calculate the volume and area of the box. Use call by reference so that your main function can have access to the variables which store the area and volume.

 

i can do the normal programming but what is the difference of it between me doing it in fucntion call by value and function call by reference 

Answer 1

Doing a function call by value copies the actual value of an argument into the formal parameter of the function. In this case, changes made to the parameter inside the function have no effect on the argument.  They do not change the value of the variable outside the function.

By default, C++ uses call by value to pass arguments. In general, this means that code within a function cannot alter the arguments used to call the function.  When you write a function, in this case named box(), it would look like this:

 

void box(int L, int W, int H){

...

...

...

}

 

Doing a function call by reference actually changes the value of the variable outside the function.  To implement this, you would write your function like this:

 

void box(int L, int W, int H, int &Area, int &Vol){
...
...
...
}

 

Answer 2

using namespace std;

#include <iostream>

CalcVolumeArea( double length, double width, double height, double * volume, double * area)

{

*volume = length*width*height;

*area = 2*(length*width + length*height + width*height);

}

int main()

{

double length,width,height,volume,area;

cout << " Please input the length :>";

cin >> length;

cout << "Please input the width :>";

cin >> width;

cout << "Please input the height :>";

cin >> height;

CalcVolumeArea(length,width,height,&volume,&area);

cout << "Length is " << length << endl;

cout << "Height is " << height << endl;

cout << "Width is " << width << endl;

cout << "Volume is " << volume << endl;

cout << "Area is " << area << endl;

}

Answer 3

#include <stdio.h>

void box(int x,int y,int z); //Function calculating area and volume of a box//

int area,volume ; // globally declared so they can be used anywhere in the program //

void main(){

int l ,b,h ;// length,breadth,height //

printf("Enter the length ,breadth and height of a box \n");

Scanf("%d%d%d",&l&b&h);//Taking the length breadth and height //

box(l,b,h);//function called //

Printf("area=%d ,Volume=%d",area,volume);

}

void box(int x,int y,int z){

Area=x*y;

Volume=x*y*z;

}