Lesson 37 Source Code

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Lesson 37 Video

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Lesson 37: Function Parameters & Return value

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Examples of parameters and return values


All calculations of any function will use the return value of the function. Here are some examples:
#include <iostream>
using namespace std;

double f()
{
	return 2.718;
}

int main()
{
	cout << f();
	cin.get();
	return 0;
}
 #include <iostream>
using namespace std;

double f()
{
	return 2.718;
}

int main()
{
	cout << 2*f()-.435;
	cin.get();
	return 0;
}


Here are some examples of functions that takes in one parameter x. x does not need to be initialized as a variable in the function x 

because it is already initialized as a parameter.
#include <iostream>
using namespace std;

double f(double x)
{
	return 2*x+1;
}

int main()
{
	cout << f(2);
	cin.get();
	return 0;
}
 #include <iostream>
using namespace std;

double f(double x)
{
	return 2*x+1;
}

int main()
{
	cout << f(2*6-3);
	cin.get();
	return 0;
}
 #include <iostream>
using namespace std;

double f(double x)
{
	return 2*x+1;
}

int main()
{
	double z=7;
	cout << f(z);
	cin.get();
	return 0;
}


The rules of scope still apply
#include <iostream>
using namespace std;

double f(double x)
{
	int y=x-3;
	return 2*x+1;
}

int main()
{
	int z=7;
	cout << f(z);
	cin.get();
	return 0;
}


Here is a function that takes two parameters of the type double
f(double x, z) will NOT be accepted by the C++ compiler
#include <iostream>
using namespace std;

double f(double x, double z)
{
	int y=x-3;
	return x*y;
}

int main()
{
	double x=7, y=21;
	cout << f(8,x) << endl << y;
	cin.get();
	return 0;
}


Here is a more complex function taht will take in multiple parameters. Copy and paste this code and change some of the values around to 

see what will happen.
#include <iostream>
using namespace std;

char f(double x, char ch, bool TheTruth)
{
	if(TheTruth)
	{
		cout << 2*x+1;
		return ch;
	}
	else
	{
		cout << (x-1)/x;
		return '|';
	}
}

int main()
{
	char smart = f(4,'z',true);
	cout << endl << smart;
	cin.get();
	return 0;
}