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2010-05-25T14:21:17Z

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==A simple exception handling example==

<source lang="cpp">#include <iostream>
using namespace std;
int main()
{
cout << "Start\n";
try {
cout << "Inside try block\n";
throw 1; // throw an error
cout << "This will not execute";
}
catch (int i) { // catch an error
cout << "Caught an exception -- value is: ";
cout <
<pre class=codeResult>Start
Inside try block
Caught an exception -- value is: 1
End"</pre>

==A try block can be localized to a function==

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

void f(int test)
{
try{
if(test) throw test;
}
catch(int i) {
cout << "Caught One! Ex. #: " <
<pre class=codeResult>start
Caught One! Ex. #: 1
Caught One! Ex. #: 2
Caught One! Ex. #: 3
end</pre>

==Catch all exceptions==

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

void f(int test)
{
try{
if(test==0) throw test; // throw int
if(test==1) throw "a"; // throw char
if(test==2) throw 123.23; // throw double
}
catch(...) { // catch all exceptions
cout << "Caught One!\n";
}
}

int main()
{
f(0);
f(1);
f(2);

return 0;
}</source>
<pre class=codeResult>Caught One!
Caught One!
Caught One!</pre>

==Catch "char *" exception==

<source lang="cpp">#include <iostream.h>
int main () {
try
{
throw "Out of range";
}
catch (char * str)
{
cout << "Exception: " << str << endl;
}
return 0;
}</source>
<pre class=codeResult>This application has requested the Runtime to terminate it in an unusual way.
Please contact the application"s support team for more information.</pre>

==Catching derived classes==

<source lang="cpp">#include <iostream>
using namespace std;
class B {
};
class D: public B {
};
int main()
{
D derived;
try {
throw derived;
}
catch(B b) {
cout << "Caught a base class.\n";
}
catch(D d) {
cout << "This won"t execute.\n";
}
return 0;
}</source>

==Multiple catch blocks==

<source lang="cpp">#include <iostream.h>
int main () {
try
{
char * mystring;
mystring = new char [10];
if (mystring == NULL)
throw "Allocation failure";

for (int n=0; n<=100; n++)
{
if (n>9)
throw n;
mystring[n]="a";

}
}
catch (int i)
{
cout << "index " <
<pre class=codeResult>index 10 is out of range</pre>

==Throwing an exception from a function called from within a try block==

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

void f(int test)
{
cout << "Inside f, test is: " << test << "\n";
if(test)
throw test;
}

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

try { // start a try block
cout << "Inside try block\n";
f(0);
f(1);
f(2);
}
catch (int i) { // catch an error
cout << "Caught an exception -- value is: ";
cout <
<pre class=codeResult>start
Inside try block
Inside f, test is: 0
Inside f, test is: 1
Caught an exception -- value is: 1
end</pre>

==try catch block without exception being thrown==

<source lang="cpp">#include <iostream>
using namespace std;
int main()
{
cout << "Start\n";
try {
cout << "Inside try block\n";
cout << "Still inside try block\n";
}
catch (int i) {
cout << "Caught an exception -- value is: ";
cout <
<pre class=codeResult>Start
Inside try block
Still inside try block
End"</pre>

==Use catch(...) as a default==

<source lang="cpp">#include <iostream>
using namespace std;
void f(int val)
{
try{
if(val==0)
throw val;
if(val==1)
throw "a";
if(val==2)
throw 123.23;
}
catch(int i) { // catch an int exception
cout << "Caught an integer\n";
}
catch(...) { // catch all other exceptions
cout << "Caught One!\n";
}
}
int main()
{
f(0);
f(1);
f(2);
return 0;
}</source>
<pre class=codeResult>Caught an integer
Caught One!
Caught One!</pre>

==Use multiple catch statements==

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

void f(int test)
{
try{
if(test)
throw test; // throw int
else
throw "Value is zero"; // throw char *
}
catch(int i) {
cout << "Caught One! Ex. #: " <
<pre class=codeResult>start
Caught One! Ex. #: 1
Caught One! Ex. #: 2
This application has requested the Runtime to terminate it in an unusual way.
Please contact the application"s support team for more information.</pre>

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