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2010-05-25T14:21:17Z

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==Compare pass-by-value and pass-by-reference with references==

<source lang="cpp">#include <iostream>
using std::cout;
using std::endl;
int byValue( int );
void byReference( int & );

int main()
{
int x = 2;
int z = 4;
cout << byValue( x ) << endl;
cout << "x = " << x << endl;
byReference( z );
cout << "z = " << z << endl;
return 0;
}
int byValue( int number )
{
return number *= number;
}
void byReference( int &numberRef )
{
numberRef *= numberRef;
}</source>
<pre class=codeResult>4
x = 2
z = 16</pre>

==Default arguments with parameters==

<source lang="cpp">#include <iostream>
using std::cout;
using std::endl;
int f( int length = 1, int width = 1, int height = 1 );
int main()
{
cout << f();

cout << f( 10 );

cout << f( 10, 5 );

cout << f( 10, 5, 2 ) << endl;
return 0;
}
int f( int length, int width, int height )
{
return length * width * height;
}</source>
<pre class=codeResult>11050100</pre>

==Define function to add two parameters together==

<source lang="cpp">#include <iostream>

int Add (int x, int y)
{
std::cout << "In Add(), received " << x << " and " << y << "\n";
return (x+y);
}

int main()
{
std::cout << "The value returned is: " << Add(3,4);
return 0;
}</source>
<pre class=codeResult>In Add(), received 3 and 4
The value returned is: 7</pre>

==Definition of function template maximum==

<source lang="cpp">#include <iostream>
using std::cout;
using std::cin;
using std::endl;

template < class T >
T maximum( T value1, T value2, T value3 )
{
T maximumValue = value1;
if ( value2 > maximumValue )
maximumValue = value2;
if ( value3 > maximumValue )
maximumValue = value3;
return maximumValue;
}

int main()
{
int int1, int2, int3;
int1 = 1;
int2 = 2;
int3 = 3;
cout << "\nThe maximum integer value is: " << maximum( int1, int2, int3 );

double double1, double2, double3;
double1 = 1.1;
double2 = 2.2;
double3 = 3.3;
cout << "\nThe maximum double value is: "<< maximum( double1, double2, double3 );
char char1, char2, char3;
char1 = "a";
char2 = "b";
char3 = "c";
cout << "\nThe maximum character value is: "<< maximum( char1, char2, char3) << endl;
return 0;
}</source>
<pre class=codeResult>The maximum integer value is: 3
The maximum double value is: 3.3
The maximum character value is: c</pre>

==Functions in an expression: order of evaluation==

<source lang="cpp">#include <iostream>
#include <ostream>
using namespace std;
int x = 1;
int f()
{
x = 2;
std::cout << "f()";
return x;
}
int g()
{
std::cout << "g()";
return x;
}
int main()
{
std::cout << f() / g() << "\n";
}</source>
<pre class=codeResult>f()g()1</pre>

==Functions that take no arguments.==

<source lang="cpp">#include <iostream>
using std::cout;
using std::endl;
void f1();
void f2( void );
int main()
{
f1();
f2();
return 0;
}
void f1()
{
cout << "f1 takes no arguments" << endl;
}
void f2( void )
{
cout << "f2 also takes no arguments" << endl;
}</source>
<pre class=codeResult>f1 takes no arguments
f2 also takes no arguments</pre>

==The function call stack and activation records==

<source lang="cpp">#include <iostream>
using std::cin;
using std::cout;
using std::endl;
int f( int );
int main()
{
int a = 10;
cout << a << " fd: " << f( a ) << endl;
return 0;
}
int f( int x )
{
return x * x;
}</source>
<pre class=codeResult>10 fd: 100</pre>

==This program contains two functions: main() and f().==

<source lang="cpp">#include <iostream>
using namespace std;

void f(); // f"s protoype

int main()
{
cout << "In main()\n";

f(); // call f()

cout << "Back in main()\n";

return 0;
}

// This if the function"s definition.
void f()
{
cout << "Inside f()\n";
}</source>
<pre class=codeResult>In main()
Inside f()
Back in main()</pre>

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