do while

soccer53 (16)
How can I make this a little bit less code and also use a do while function?

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#include <iostream>
#include <cmath>
#include <iomanip>
using namespace std;
#define PI acos(-1)
void printSpaces(){
cout<<endl<<"##########################################################"<<endl<<endl;
}
void volumeOfCone(){
printSpaces();
double radius, height, volume;
// Taking relevant inputs
cout<<"Enter radius of base of cone"<<endl;
cin>>radius;
cout<<"Enter height of cone"<<endl;
cin>>height;
// Error Checking
if(radius<0 || height<0){
cout<<"Incorrect Input. Please Try Again"<<endl;
volumeOfCone();
}
/*
Volume = (PI*radius*radius*height)/3
*/
// Calculating
volume = (PI*pow(radius, 2)*height)/3;
// Printing Outputs
cout<<"For the input radius = "<<radius<<" and height = "<<height<<endl;
cout<<"The volume of Cone is "<<fixed<<setprecision(2)<<volume<<endl;
printSpaces();
}
void volumeOfSphere(){
printSpaces();
double radius, volume;
// Taking relevant inputs
cout<<"Enter radius of sphere"<<endl;
cin>>radius;
// Error Checking
if(radius<0){
cout<<"Incorrect Input. Please Try Again"<<endl;
volumeOfSphere();
}
/*
Volume = (4*PI*radius*radius*radius)/3
*/
// Calculating
volume = (4*PI*pow(radius, 3))/3;
// Printing Outputs
cout<<"For the input radius = "<<radius<<endl;
cout<<"The volume of Sphere is "<<fixed<<setprecision(2)<<volume<<endl;
printSpaces();
}
void areaOfOctagon(){
printSpaces();
double side, area;
// Taking relevant inputs
cout<<"Enter the side of Octagon"<<endl;
cin>>side;
// Error Checking
if(side<0){
cout<<"Incorrect Input. Please Try Again"<<endl;
areaOfOctagon();
}
/*
Area = 2*(1+sqrt(2))*side*side
*/
// Calculating
area = 2*(1+sqrt(2))*pow(side,2);
// Printing Outputs
cout<<"For the input side = "<<side<<endl;
cout<<"The Area of Octagon is "<<fixed<<setprecision(2)<<area<<endl;
printSpaces();
}
void distanceBetweenTwoPoints(){
printSpaces();
double distance;
// Initializing structure for a coordinate
struct Point{
double x;
double y;
};
Point first, second;
// Taking relevant inputs
cout<<"Enter values as asked"<<endl;
cout<<"First Point"<<endl;
cout<<"Enter X Coordinate: ";
cin>>first.x;
cout<<"Enter Y Coordinate: ";
cin>>first.y;
cout<<"Second Point"<<endl;
cout<<"Enter X Coordinate: ";
cin>>second.x;
cout<<"Enter Y Coordinate: ";
cin>>second.y;
/*
distance = sqrt(pow((x1-x2), 2) + pow((y1-y2), 2))
*/
// Calculating
distance = sqrt( pow(first.x-second.x, 2) + pow(first.y-second.y, 2));
// Printing Outputs
cout<<"Points were ("<<first.x<<" , "<<first.y<<") and "<<"("<<second.x<<" , "<<second.y<<")"<<endl;
cout<<"The Distance between these points is "<<fixed<<setprecision(2)<<distance<<endl;
printSpaces();
}
int main(){
while(1){
cout<<endl<<"Pick an option from choices below"<<endl;
cout<<"1. Find Volume of Cone "<<endl;
cout<<"2. Find Volume of Sphere"<<endl;
cout<<"3. Find Area of Octagon"<<endl;
cout<<"4. Find Distance between two points"<<endl;
cout<<"5. Stop"<<endl<<endl;
int choice;
cout<<"Enter your choice here: "<<endl;
cin>>choice;
if(choice == 5)
break;
switch(choice){
case 1: volumeOfCone();
break;
case 2: volumeOfSphere();
break;
case 3: areaOfOctagon();
break;
case 4: distanceBetweenTwoPoints();
break;
default: cout<<"You have entered an invalid option. Please Try again"<<endl;
}
}
}
Last edited on
Handy Andy (5051)
Hello soccer53,

A possible reason you have not received a responce may be due to how difficult your code is to read.

With a few blank lines and some indenting your code could look lime this:
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#include <iostream>
#include <cmath>
#include <iomanip>

using namespace std;  // <--- Best not to use.

#define PI acos(-1)

void printSpaces()
{
	cout << endl << "##########################################################" << endl << endl;
}

void volumeOfCone()
{
	printSpaces();
	double radius, height, volume;
	// Taking relevant inputs
	cout << "Enter radius of base of cone" << endl;
	cin >> radius;
	cout << "Enter height of cone" << endl;
	cin >> height;
	// Error Checking
	if (radius<0 || height<0)
	{
		cout << "Incorrect Input. Please Try Again" << endl;
		volumeOfCone();
	}
	/*
	Volume = (PI*radius*radius*height)/3
	*/
	// Calculating
	volume = (PI*pow(radius, 2)*height) / 3;
	// Printing Outputs
	cout << "For the input radius = " << radius << " and height = " << height << endl;
	cout << "The volume of Cone is " << fixed << setprecision(2) << volume << endl;
	printSpaces();
}

void volumeOfSphere()
{
	printSpaces();
	double radius, volume;
	// Taking relevant inputs
	cout << "Enter radius of sphere" << endl;
	cin >> radius;
	// Error Checking
	if (radius<0)
	{
		cout << "Incorrect Input. Please Try Again" << endl;
		volumeOfSphere();
	}
	/*
	Volume = (4*PI*radius*radius*radius)/3
	*/
	// Calculating
	volume = (4 * PI*pow(radius, 3)) / 3;
	// Printing Outputs
	cout << "For the input radius = " << radius << endl;
	cout << "The volume of Sphere is " << fixed << setprecision(2) << volume << endl;
	printSpaces();
}

void areaOfOctagon()
{
	printSpaces();
	double side, area;
	// Taking relevant inputs
	cout << "Enter the side of Octagon" << endl;
	cin >> side;
	// Error Checking
	if (side<0)
	{
		cout << "Incorrect Input. Please Try Again" << endl;
		areaOfOctagon();
	}
	/*
	Area = 2*(1+sqrt(2))*side*side
	*/
	// Calculating
	area = 2 * (1 + sqrt(2))*pow(side, 2);
	// Printing Outputs
	cout << "For the input side = " << side << endl;
	cout << "The Area of Octagon is " << fixed << setprecision(2) << area << endl;
	printSpaces();
}

void distanceBetweenTwoPoints()
{
	printSpaces();
	double distance;
	// Initializing structure for a coordinate
	struct Point
	{
		double x;
		double y;
	};

	Point first, second;

	// Taking relevant inputs
	cout << "Enter values as asked" << endl;
	cout << "First Point" << endl;
	cout << "Enter X Coordinate: ";
	cin >> first.x;
	cout << "Enter Y Coordinate: ";
	cin >> first.y;
	cout << "Second Point" << endl;
	cout << "Enter X Coordinate: ";
	cin >> second.x;
	cout << "Enter Y Coordinate: ";
	cin >> second.y;
	/*
	distance = sqrt(pow((x1-x2), 2) + pow((y1-y2), 2))
	*/
	// Calculating
	distance = sqrt(pow(first.x - second.x, 2) + pow(first.y - second.y, 2));
	// Printing Outputs
	cout << "Points were (" << first.x << " , " << first.y << ") and " << "(" << second.x << " , " << second.y << ")" << endl;
	cout << "The Distance between these points is " << fixed << setprecision(2) << distance << endl;
	printSpaces();
}

int main()
{
	int choice{};
	bool cont{ true };  // <---Added.

	while (cont) // <--- Changed.
	{
		cout << endl << "Pick an option from choices below" << endl;
		cout << "1. Find Volume of Cone " << endl;
		cout << "2. Find Volume of Sphere" << endl;
		cout << "3. Find Area of Octagon" << endl;
		cout << "4. Find Distance between two points" << endl;
		cout << "5. Stop" << endl << endl;
		cout << "Enter your choice here: ";  // <--- Endl nor needed here.
		cin >> choice;

		//if (choice == 5)  // <--- Moved to switch.
		//	break;

		switch (choice)
		{
			case 1:
				volumeOfCone();
				break;
			case 2:
				volumeOfSphere();
				break;
			case 3:
				areaOfOctagon();
				break;
			case 4:
				distanceBetweenTwoPoints();
				break;
			case 5: // <--- Moved if statement here.
				cont = false;
				break;
			default: cout << "You have entered an invalid option. Please Try again" << endl;
		}  //  End switch.
	}  //  End While loop.

	// The next line may not be needid. If you have to press enter to see the prompt it is not needed.
	std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');  // <--- Requires header file <limits>.
	std::cout << "\n\n Press Enter to continue";
	std::cin.get();

	return 0;
}

As you can see the above code is much easier to read and follow.

Changing the while loop to a do/while will make no difference to the program because the while condition always starts as true, so it will always execute one time.

An example of a do/while loop would be:
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int main()
{
	int choice{};
	bool cont{ true };  // Added.

	do
	{
		cout << endl << "Pick an option from choices below" << endl;
		cout << "1. Find Volume of Cone " << endl;
		cout << "2. Find Volume of Sphere" << endl;
		cout << "3. Find Area of Octagon" << endl;
		cout << "4. Find Distance between two points" << endl;
		cout << "5. Stop" << endl << endl;
		cout << "Enter your choice here: ";  // <--- Endl nor needed here.
		cin >> choice;

		//if (choice == 5)  // <--- Moved to switch.
		//	break;

                switch (choice)
		{
			case 1:
				volumeOfCone();
				break;
			case 2:
				volumeOfSphere();
				break;
			case 3:
				areaOfOctagon();
				break;
			case 4:
				distanceBetweenTwoPoints();
				break;
			case 5: // <--- Moved if statement here.
				cont = false;
				break;
			default: cout << "You have entered an invalid option. Please Try again" << endl;
		}  //  End switch.

	} while (cont); //  End While / do/while loop. Changed for do/while.

	// The next line may not be needed. If you have to press enter to see the prompt it is not needed.
	std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');  // <--- Requires header file <limits>.
	std::cout << "\n\n Press Enter to continue";
	std::cin.get();

	return 0;
}

Right now I see no benefit between the while loop and a do/while loop. As setup they both work the same way.

Hint: try adding the line "#define _USE_MATH_DEFINES" before you include <cmath>. If this should not work the #define needs to go before "#include <math.h>" which is done in the "cmath" header file. Personally I edited my "cmath" file and put the "#define" right before the "#incluse" for "math.h". This opens several "#define" variables like "M_PI" and others. This is found at the end of the "math.h" header file. This way you do not have to calculate "PI" just use "M_PI". It comes out the same.

Suggestion: Most of your lines that require a set of {}s to define a block have the opening { at the end of the line. It is better to press enter and start the opening { on the next line and having the closing } in the same column. Take a look at your functions in the first code for an example. Benefits of this are that it is easier to read and when the {}s line up in the same column, along with proper indenting, it is easier to find one that is messing. Also notice the comments I put on the closing }s to let people know what they go to. This also helps you.

Either way is acceptable and the compiler case nothing about white space, so it is better to make your code readable than compact.

One other thing I noticed is that you should initialize your variables when defined. This is not always necessary, but a goo idea to get use to before it becomes a problem. From C++11 on the use of empty {}s will give numeric variables a value of zero and "char" variables a value of "\0" "floats" and "doubles" would be "0.0". "std::strings" "std::vectors" and some others are defined with a zero size and do not need initialized.

Any other questions let me know.

Hope that helps,

Andy
jonnin (11441)
you can clean up a bit for sure.

a function to do error checking that you do over and over would reduce that.
a function for your input output statements with a parameter, maybe, eg:

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double getuserinput(string s)
{
    double d = -1;
    cout << enter a value for << s << endl;
    do
     {
       cin >> d;
     }
    while (!validateinput(d))
    return d;    
}


and so on. Much of your code is redundant, find anything you do more than twice, and put it into a function.
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