try/catch/throw exceptions

Hello,

I have a program where I am calculating a number and then taking the inverse of it (i.e: 1/x), I am going through this calculation many times...but there are times when x=0, which will make it not possible to take the invese of(i.e 1/0)......I am attempting to use a try /catch/throw method....my function's name is solver, and it is being called in main:

int main(){

try { solver(); }
}

now the function:

void solver(){

//this is where my ? is, I just need to check is if x == 0??

if (x == 0){

//is this exception, or do I write invalid_argument or range_error
//or is it basically anything I want it to be, are they biult in?

throw_exception("x found to be 0";)
}

//now back to main
int main() {
try { solver(); }

catch(exception ){

cout<<"error, 0 calculated<<endl;}//end catch

}

I am getting a many errors with this...and since I've never used try/catch/throw...I am not sure what I am doing wrong...

also, when it does catch an exception, does it exit the program?
or is there a way to catch the exception and go to the next iteration and next calculation?? thanks for any help...

The syntax should be something like -

Code:

---

#include <iostream>

using namespace std;

void solver(int x){
        if (x == 0)
      throw ("x found to be 0") ;
}

int main() {
        try { solver(0); }
        catch(char* a){
        cout<<a << '\n' ; //end catch
        }
        return 0;
}

---

If you don't wish to exit the program you'll either have to call the solver function again after it has thrown or move your try/catch block into the solver function.

hello...

I'm having some trouble figuring out why my code is not catching exceptions...

I have tried the syntax suggested above...but nothing is getting printed to the screen about getting the 0...this is the code:


int main(){

makesolver sheet(); }


void makesolversheet() {

get();

bestfit(); //this is the function that is calculating a slope value

}//end makesolversheet


void bestfit() {

--some calculations--

if (slope == 0){

try { tryslope(slope); }//if slope is 0

}//end try

catch (char* a) {

cout <<a<<'\n'; } //end catch

}//end bestfit



void tryslope(float x) {

if (x == 0)
{ throw ("slope calc. to be 0"); }


}//end tryslope


I have assigned in my code for slope to be 0 so that it enters the loop in the bestfit function and tryslope gets called...however when I run it...the statement: "slope calc to be 0" is not showing up... ( My main need is to be able to go through many calculaiton of the slope...when 0 is caluculated...let the user know and move on to the next calculation...not exiting the program)...however this is not even printing that 0 was calc...any help will be greatly appreciated... thanks

here's a reference site that discusses try/catch. May not be the best explanation, but it's a place to start.

http://www.stud.fim.ntnu.no/~oystesk...0.htm#Heading2


based on that reference and on how I interpret your code I would consider doing something like this:


//declare the exception class before main()
class zeroDenom {};

int main(){

makesolver sheet(); }


void makesolversheet() {

get();

bestfit(); //this is the function that is calculating a slope value

}//end makesolversheet

try{
void bestfit() {

--some calculations--
if(x == 0)
throw zeroDenom();
//more calculations
} //end bestfit()
}//end try

catch (zeroDenom) {

cout << "cannot divide by zero" << '\n'; } //end catch

}//end specific catch
catch(...)
{
cout << "unexplained failure" << endl;
}//end non-specific catch