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Function not calling a variable

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Join Date: Oct 2008

Posts: 18

Reputation: Dontais is an unknown quantity at this point

Solved Threads: 0

Dontais

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Newbie Poster

Function not calling a variable

Nov 22nd, 2008

When I compile the program it returns "error C2065: 'answer' : undeclared identifier". I thought answer was declared from the function and would call answer. Any tips where I'm going wrong on this. The program is made to out put Radius, cosx(x), and a user defined cosx in 3 rows.

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
 
double cosx (int x, int answer);
 
int main () 
{
for (double x = 0.0; x <= 3.1; x = x + .1) 
{
	cout << "Radians" << setw(6) << "Cousines by cos(x)" << setw(15) << "Cousines by user defined" << endl; 
	cout << setprecision(2) << fixed << x << setw(6) << cos(x) << setw(15) << cosx (x, answer) << endl;
}
}
 
double cosx (int x, int answer)
{
	int n, num, denom, ans, term, count; 
	n = 2; 
 
	while (ans >= .000001)
	{
		for (int i = 0; i <= n; n++)
		{
			num = num*n;
		}
		for (int  k = num; k >= 1; k--)
		{
			denom = denom*k; 
		}
		term =  num/denom; 
 
		if ((term%11)== 0)
			ans = ans + term; 
		else 
			ans = ans - term; 
		count++; 
		n+= 2; 
	}
	return ans; 
}
double cosx (int x, int answer);

int main () 
{
for (double x = 0.0; x <= 3.1; x = x + .1) 
{
	cout << "Radians" << setw(6) << "Cousines by cos(x)" << setw(15) << "Cousines by user defined" << endl; 
	cout << setprecision(2) << fixed << x << setw(6) << cos(x) << setw(15) << cosx (x, answer) << endl;
}
}

double cosx (int x, int answer)
{
	int n, num, denom, ans, term, count; 
	n = 2; 

	while (ans >= .000001)
	{
		for (int i = 0; i <= n; n++)
		{
			num = num*n;
		}
		for (int  k = num; k >= 1; k--)
		{
			denom = denom*k; 
		}
		term =  num/denom; 

		if ((term%11)== 0)
			ans = ans + term; 
		else 
			ans = ans - term; 
		count++; 
		n+= 2; 
	}
	return ans; 
}

•

Join Date: Jul 2008

Posts: 2,001

Reputation: ArkM has much to be proud of

Solved Threads: 343

ArkM

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Postaholic

Re: Function not calling a variable

Nov 22nd, 2008

A function can't "call a variable". It may be called (from another functions) and may call another functions.
The parameter name "answer" in cosx header does not bear a relation to a word "answer" in the main function body. You must declare int variable (called answer or what else) in main and assign a value to this variable before using it in cosx call.
No need in the 2nd parameter of cosx at all. Look at cosx body: you don't use the 2nd parameter.
There are lots of another defects in your code. You declare the 1st parameters of cosx as int but obviously treat it as double. You compare ans (why int again? ) unitialized variable with 0.00001 double value in while loop conditional expression. You don't initialize num and denom variables too.
Correct the code and try again...

•

Join Date: Oct 2008

Posts: 18

Reputation: Dontais is an unknown quantity at this point

Solved Threads: 0

Dontais

Offline

Newbie Poster

Re: Function not calling a variable

Nov 27th, 2008

I am on my second attempt on this program but it doesn't output right.

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
 
#include <iostream> 
using std::cin; 
using std::cout; 
using std::endl; 
using std::fixed;
 
#include <iomanip> 
using std::setw;
using std::setprecision; 
 
#include <cmath> 
 
 
double cosx (double x);
 
int main () 
{
	double x = 0.0, result1, result2; 
 
 
		cout << " Radians" << "Cousines by cos(x)" << setw(10) << "Cousines by user defined" << endl; 
 
 
		while(x < 3.2)
		{
			result1 = cos(x); 
			result2 = cosx(x); 
 
			cout << setw(10) << fixed << setprecision(2) << x << setw(10) << setw(10) << result1 << setw(10)
				<< result2 << endl; 
			x = x + .1; 
		}
 
return 0; 
}
 
double cosx (double x)
{
	double num, denom, ans, term;
	int n, count; 
	n = 2;
	ans = 1; 
	term = 1; 
	count = 1; 
 
	while (fabs(term) >= .000001)
	{
		num =1; 
		for (int i = 1; i <= n; n++)
			{
				num = num*n;
			}
 
		denom = 1; 
		for (int  k = n; k >= 1; k--)
		{
				denom = denom*k; 
		}
 
		term =  num/denom; 
 
		if ((count%2) == 0)
		{
			ans = ans + term; 
		}
		else 
		{
			ans = ans - term; 
		}
		count++; 
		n+= 2; 
	}
 
	return ans; 
}
#include <iostream> 
using std::cin; 
using std::cout; 
using std::endl; 
using std::fixed;

#include <iomanip> 
using std::setw;
using std::setprecision; 

#include <cmath> 


double cosx (double x);

int main () 
{
	double x = 0.0, result1, result2; 
 

		cout << " Radians" << "Cousines by cos(x)" << setw(10) << "Cousines by user defined" << endl; 

	
		while(x < 3.2)
		{
			result1 = cos(x); 
			result2 = cosx(x); 

			cout << setw(10) << fixed << setprecision(2) << x << setw(10) << setw(10) << result1 << setw(10)
				<< result2 << endl; 
			x = x + .1; 
		}

return 0; 
}

double cosx (double x)
{
	double num, denom, ans, term;
	int n, count; 
	n = 2;
	ans = 1; 
	term = 1; 
	count = 1; 

	while (fabs(term) >= .000001)
	{
		num =1; 
		for (int i = 1; i <= n; n++)
			{
				num = num*n;
			}

		denom = 1; 
		for (int  k = n; k >= 1; k--)
		{
				denom = denom*k; 
		}
		
		term =  num/denom; 
		
		if ((count%2) == 0)
		{
			ans = ans + term; 
		}
		else 
		{
			ans = ans - term; 
		}
		count++; 
		n+= 2; 
	}

	return ans; 
}