getting weird answer when not using ".h"

i made a simple program that multiplies to numbers you enter. if you enter a letter the answer comes out to 0. all this time i was using <iostream.h>, so i decided to skip the .h and put using namespace std. after doing so it multiplied numbers fine, but when i enter a letter the answer would come out to something like 9852459. anyone know why???

Can you show me the code?

I think the behavior of the new iostreams differs from the old in that:
In the old, if a >> operator couldn't parse a number it would read 0.
In the new it reads undefined, thus the variable doesn't change its (random) initial value.

cin.good() returns false if the operator failed to read the variable type.

show the code. You can just make a safe-input setup so it only calculates the intended data type.

You can also tell the stream to throw an exception.

I think you might be using the wrong variable type.Decide the range of input nos. that you desire and then use the proper variable type,such as ''unsigned long''
Also,along with the code,state the compiler that u r using and its version.
Use simple if..then or switch statements to handle exeptions.

Show some code

All characters are represented in memory by a numeric assignment.
For example "F" is represented by 38 in the ASCII character set,
"f" is represented by 102.

You may have to declare your variables a char to avoid numeric representation.

namespace std appears to convert to ASCII with your compiler

ok heres the code:

Code:

---

#include <iostream>

using namespace std;

int main()

{
        int x,y;
       
        cout<<"Please enter a number: ";
       
        cin>>x;

        cout<<"Please enter another number: ";

        cin>>y;

        cout<<"The Final Number is: "<<x * y <<endl;

        return 0;

}

---

If you were to enter a letter in error, the input read would fail, and the contents of the int variable would be unreliable.

You might want to check through these to see if any help you.

A simple fix to your program might be:

Code:

---

#include <iostream>

using namespace std;

int main()
{
  int x,y;
 
  cout<<"Please enter a number: ";
 
  if (cin>>x)
  {
    cout<<"Please enter another number: ";
    if (cin>>y)
    {
      cout<<"The Final Number is: "<<x * y <<endl;
    }
  }
}

---

Or:

Code:

---

#include <iostream>

using namespace std;

int main()
{
  int x,y;
 
  cout<<"Please enter a number: ";
 
  while(!(cin>>x))
  {
    cin.clear();
    cin.ignore(cin.rdbuf()->in_avail());
    cout << "Not a number. Please enter a number: ";
  }
  cout<<"Please enter another number: ";
  while(!(cin>>y))
  {
    cin.clear();
    cin.ignore(cin.rdbuf()->in_avail());
    cout << "Not a number. Please enter a number: ";
  }
  cout<<"The Final Number is: "<<x * y <<endl;
}

---

Quote:

---

Originally posted by bookworm
Hey Cobra, C++ books are not so fat for nothing.
True,this is a simple program,but not so simple that u can get away without using FUNCTIONS !!!
The program is simple because u dont need to embed the functions in classes.

---

What is this post about? :confused:
What have functions to do with his problem, especially functions as useless as product()?

He IS using a function: main.

>>> He IS using a function: main.

And he returns from it correctly...!