Glass Rod Problem and big loop problem!

**TessaG** · 04-11-2015

I have been having some trouble with the loop in this problem. It is supposed to run 1,000,000 times, but I can not seem to get it to initialize more than 2 times even though I have tried all different types of loops. Can anyone give me a suggestion or where to start?
First semester programmer here.

The top comments are the basic instructions of how to format the program.

Code:

//void function 2 random numbers>=1 <=999 with data validation to eliminate duplicates
//void function 2 IN, return 3 out for lengths of pieces (5 paramaters)
//bool function to accept 3 lenghts, return statement in bool value of false if no triangle made (3 paramaters)
//main function, loop to run 1,000,000 times. display results. seed random on system time.


#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;


void randomNumbers(int & firstBreak, int & secondBreak);
void lengthOfPieces(int & firstBreak, int & secondBreak, int & sideOne, int & sideTwo, int & sideThree);
bool isTriangle(int & sideOne, int & sideTwo, int & sideThree);


void main ()
{
	int count= 0;
	int triangle = 0;
	bool status;
	int notTriangle = 0;
	int firstBreak, secondBreak, sideOne, sideTwo, sideThree;


	unsigned seed = time(0);
	srand(seed);


	randomNumbers (firstBreak, secondBreak);
	lengthOfPieces (firstBreak, secondBreak, sideOne, sideTwo, sideThree);
	isTriangle (sideOne, sideTwo, sideThree);
	
//	if (status = true)
//	{
//		triangle++;
//	}
//	else if (status = false)
//	{
//		notTriangle++;
//	}
	
	
	
	notTriangle = 1000000 - triangle;


	cout << "The rod dropped 1,000,000 times and created a triangle " << triangle <<  " times." << endl;
	cout << "The rod did not create a triangle " << notTriangle <<  " times." << endl;
}


void randomNumbers (int & firstBreak, int & secondBreak)
{
	do 
	{
	firstBreak = rand () % 999 + 1;
	secondBreak = rand () % 999 + 1;
	}
	while (firstBreak == secondBreak);
}


void lengthOfPieces (int & firstBreak, int & secondBreak, int & sideOne, int & sideTwo, int & sideThree)
{
	if (firstBreak < secondBreak)
(sideOne = firstBreak + 1) && (sideTwo = secondBreak - (firstBreak + 1)) && (sideThree = 1000 - (sideOne + sideTwo));    
	else 
(sideOne = secondBreak + 1) && (sideTwo = firstBreak - (secondBreak + 1)) && (sideThree = 1000 - (sideOne + sideTwo)); 
}


bool isTriangle (int & sideOne, int & sideTwo, int & sideThree)
{
	bool status;
	if (sideOne + sideTwo > sideThree || sideTwo + sideThree > sideOne || sideOne + sideThree > sideTwo)
		status = true;
	else
		status = false;


	return status;
}

**Salem** · 04-12-2015

> if (status = true)
You need to know that there is a difference between = and ==

> (sideOne = firstBreak + 1) && (sideTwo = secondBreak - (firstBreak + 1)) && (sideThree = 1000 - (sideOne + sideTwo));
You NEED to know that if the left hand side of the && evaluates to false, the right hand side DOES NOT HAPPEN!
Embedded assignments in an && or || expression are a train wreck!

Do it properly, and stop trying to overly compress your code.

Guest · 04-12-2015

Unless I'm blind, you haven't specified a loop yet. A basic one might look as follows:

Code:

for(int i = 0; i < 1000000; ++i) {
    // put stuff here to be executed a million times
}

You can also use scientific notation (i < 1e6), which is convenient for large numbers.

Since the isTriangle() function returns bool, you will need to query it for that, otherwise the result simply gets discarded.

Code:

int main()
{
    bool status;
    // ...
    status = isTriangle(sideOne, sideTwo, sideThree);
}

If you don't modify the integer arguments passed to the function, they should be passed by value instead if reference:

Code:

bool isTriangle (int sideOne, int sideTwo, int sideThree)
{
    // ...
}

Also consider that your (sideOne + SideTwo > ...) expression returns bool. So you're basically saying if(true), then value = true; return true;
Try to think of a way to simplify that logic. (The 6 lines can be reduced to just a single expression)

main()'s return type is always int:

Code:

int main()
{ }

All beginnings are hard, good luck!

**TessaG** · 04-12-2015

Code:

//void function2 random numbers>=1 <=999 with data validation, eliminate duplicates
//void function 2 IN, return 3 out for lengths of pieces (5 paramaters)
//bool function to accept 3 lenghts, return statement in bool value of false if no triangle made (3 paramaters)
//main function, loop to run 1,000,000 times. display results. seed random on system time.


#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;


void randomNumbers(int & firstBreak, int & secondBreak);
void lengthOfPieces(int & firstBreak, int & secondBreak, int & sideOne, int & sideTwo, int & sideThree);
bool isTriangle(int sideOne, int sideTwo, int sideThree);


void main ()
{
	int count= 0;
	int triangle = 0;
	bool status;
	int notTriangle = 0;
	int firstBreak, secondBreak, sideOne, sideTwo, sideThree;


	unsigned seed = time(0);
	srand(seed);


	randomNumbers (firstBreak, secondBreak);
	lengthOfPieces (firstBreak, secondBreak, sideOne, sideTwo, sideThree);
	
	
	for (count = 0; count <=1000000; count++)
	{
		status = isTriangle (sideOne, sideTwo, sideThree);
		if (status == 1)
			triangle++;
		else if (status == 0)
			notTriangle++;
	}




	cout << "The rod dropped 1,000,000 times and created a triangle " << triangle <<  " times." << endl;
	cout << "The rod did not create a triangle " << notTriangle <<  " times." << endl;
}


void randomNumbers (int & firstBreak, int & secondBreak)
{
	do 
	{
	firstBreak = rand () % 999 + 1;
	secondBreak = rand () % 999 + 1;
	}
	while (firstBreak == secondBreak);
}


void lengthOfPieces (int & firstBreak, int & secondBreak, int & sideOne, int & sideTwo, int & sideThree)
{
	sideOne = 1000 - (firstBreak + secondBreak);
	sideTwo = 1000 - sideOne - firstBreak;
	sideThree = 1000 - secondBreak;
}


bool isTriangle (int sideOne, int sideTwo, int sideThree)
{
	bool status;
	if (sideOne + sideTwo > sideThree || sideTwo + sideThree > sideOne || sideOne + sideThree > sideTwo)
		status = true;
		return status;
}

I am compiling fine, but the answer I am getting is
"The rod dropped 1,000,000 times and made a triangle 1,000,0001 times.
The rod did not make a triangle 0 times."

I have done the counter, called the function inside because I need it to run 1000000 times, the trouble seems to be getting it to count the number of true/false properly. Status can return either one so I had to use another variable.

**TessaG** · 04-12-2015

I have also tried the loop this way with no avail...

Code:

for (count = 0; count <=1000000; count++)
	{
		if (status = true)
			triangle++;
		else
			notTriangle++;


		status = isTriangle (sideOne, sideTwo, sideThree);
	}

**laserlight** · 04-12-2015

Recall that status = true assigns true to status. You probably wanted to write status == true, though I would prefer just writing status since it is already a bool.

Note that if you write the assignment to status at the end of the loop body, then you need to give status a value before the loop.

**TessaG** · 04-12-2015

In variable declaration I did change:
bool status = false;

Code:

	for (count = 0; count <=1000000; count++)
	{
		status = isTriangle (sideOne, sideTwo, sideThree);
		if (status)
			triangle++;
		else
			notTriangle++;
	}

Still returns:
"The rod dropped 1,000,000 times and made a triangle 1,000,0001 times.
The rod did not make a triangle 0 times."

**laserlight** · 04-12-2015

You need to initialise status in isTriangle too. Actually, I would just write:

Code:

bool isTriangle(int sideOne, int sideTwo, int sideThree)
{
    return sideOne + sideTwo > sideThree || sideTwo + sideThree > sideOne || sideOne + sideThree > sideTwo;
}

Likewise:

Code:

for (count = 0; count < 1000000; count++)
{
    if (isTriangle(sideOne, sideTwo, sideThree))
    {
        triangle++;
    }
    else
    {
        notTriangle++;
    }
}

I changed your loop condition to count < 1000000 because you probably wanted that: generally, we start from 0 then use strictly less than, or start from 1 then use less than or equal to.

**TessaG** · 04-12-2015

It is still not counting correctly - 0 false answers, 1,000,000 true answers - results should be about 25%

**laserlight** · 04-12-2015

What is your current code?

EDIT:
Why do you terminate the loop in your randomNumbers function when firstBreak == secondBreak?

**TessaG** · 04-12-2015

We are supposed to validate that we do not have any duplicate random numbers, so I thought that it would keep running if they were the same. Been playing with the loop and what I have in now causes the program to not run...

Code:

//void function2 random numbers>=1 <=999 with data validation, eliminate duplicates
//void function 2 IN, return 3 out for lengths of pieces (5 paramaters)
//bool function to accept 3 lenghts, return statement in bool value of false if no triangle made (3 paramaters)
//main function, loop to run 1,000,000 times. display results. seed random on system time.


#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;


void randomNumbers(int & firstBreak, int & secondBreak);
void lengthOfPieces(int & firstBreak, int & secondBreak, int & sideOne, int & sideTwo, int & sideThree);
bool isTriangle(int sideOne, int sideTwo, int sideThree);


int main ()
{
	int count= 0;
	int triangle = 0;
	bool status = false;
	int notTriangle = 0;
	int firstBreak, secondBreak, sideOne, sideTwo, sideThree;


	unsigned seed = time(0);
	srand(seed);


	randomNumbers (firstBreak, secondBreak);
	lengthOfPieces (firstBreak, secondBreak, sideOne, sideTwo, sideThree);
	
	
	for (count = 0; count < 1000000; count++)
	{
		
		while (count < 1000000)
			(isTriangle(sideOne, sideTwo, sideThree));
			triangle++;
			notTriangle++;
			count++;
	}


	cout << "The rod dropped 1,000,000 times and created a triangle " << triangle <<  " times." << endl;
	cout << "The rod did not create a triangle " << notTriangle <<  " times." << endl;


	return 0;
}


void randomNumbers (int & firstBreak, int & secondBreak)
{
	do 
	{
	firstBreak = rand() % 999 + 1;
	secondBreak = rand() % 999 + 1;
	}
	while (firstBreak == secondBreak);
}


void lengthOfPieces (int & firstBreak, int & secondBreak, int & sideOne, int & sideTwo, int & sideThree)
{
	sideOne = 1000 - (firstBreak + secondBreak);
	sideTwo = 1000 - sideOne - firstBreak;
	sideThree = 1000 - secondBreak;
}


bool isTriangle (int sideOne, int sideTwo, int sideThree)
{


	return sideOne + sideTwo > sideThree || sideTwo + sideThree > sideOne || sideOne + sideThree > sideTwo;


}

**laserlight** · 04-12-2015

Originally Posted by TessaG

We are supposed to validate that we do not have any duplicate random numbers, so I thought that it would keep running if they were the same.

Oh, my mistake, I misread it. That said, it would be better to write:

Code:

firstBreak = rand () % 999 + 1;
do
{
    secondBreak = rand () % 999 + 1;
}
while (firstBreak == secondBreak);

Anyway, it looks like you are not calling randomNumbers and lengthOfPieces from within the loop, so the loop keeps working with the same values.

**TessaG** · 04-12-2015

Code:

for (count = 0; count < 1000000; count++)
	{
		randomNumbers (firstBreak, secondBreak);
		lengthOfPieces (firstBreak, secondBreak, sideOne, sideTwo, sideThree);
		isTriangle(sideOne, sideTwo, sideThree);
			if (status)
			triangle++;
			else
				notTriangle++;
	}

returns true 0 times, false 1000000 times.. thoughts?

**laserlight** · 04-12-2015

You forgot to assign the return value of the isTriangle call to status.

**TessaG** · 04-12-2015

noted - changed to:

Code:

for (count = 0; count < 1000000; count++)
	{
		randomNumbers (firstBreak, secondBreak);
		lengthOfPieces (firstBreak, secondBreak, sideOne, sideTwo, sideThree);
		status = isTriangle(sideOne, sideTwo, sideThree);
			if (status == true)
			triangle++;
			else
				notTriangle++;
	}

all true results.

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