Stupid C++ question

[techteen143]

I am making a calculator and am having some problems.
It is supposed to take a selection of either addition subtraction multiplication division or power and print the answer. The problem is in my while loop, just started these so I need some help. here is part of the program:

#include <iostream.h>
#include <math.h>

int main(void)
{
char choice;
double num , sum;
cout << "\t\t Simple Math Calculator \n\n" << endl;
cout << "select 'A' for addition, 'S' for subtraction, 'D' for division, \n";
cout << "'M' for multiplication, and 'P' for power";
cin >> choice;
if((choice == 'a') || (choice == 'A'))
{
cout << "Input numbers to be added and '.' to finish" << endl;
while(choice != '.')
{
cin >> num;
num ++;
sum = num + num;
cout << "Answer = " << sum << endl;
}
cin >> choice;
}
return 0;
}

The problem is when I input for example: 3 2 1
I get:
Answer = 8
Answer = 6
Answer = 4

and when I add the period it is infinite, what did I do wrong?

If you actually took the time to read this thanks.

[techteen143]

This part:


while(choice != '.')
{
cin >> num;
num ++;
sum = num + num;
cout << "Answer = " << sum << endl;
}
cin >> choice;
}



Thanx

[jkrohn]

cin >> choice;

need to be INSDE the while loop

Otherwise the code never even bothers to touch it.

Jkrohn

[techteen143]

Thanx BUT
If I do that when I input 3 2 1
It prints:
Answer = 8
answer = 4

*edit*

& I still get an infinite loop when running it multiple times without restarting

[vb6]

#include <iostream.h>
#include <math.h>

int main(void)
{
char choice;
int lastsum=0;
double num , sum;
cout << "\t\t Simple Math Calculator \n\n" << endl;
cout << "select 'A' for addition, 'S' for subtraction, 'D' for division, \n";
cout << "'M' for multiplication, and 'P' for power";
cin >> choice;
if((choice == 'a') || (choice == 'A'))
{
cout << "Input numbers to be added and '.' to finish" << endl;
while(choice != '.')
{
cin >> num;
sum = lastsum + num;
cout << "Answer = " << sum << endl;
lastsum = sum;
}
cin >> choice;
}
return 0;
}

Ok try this. You should be fine.
Erorr
"sum = num + num "

[techteen143]

OK I am still getting multiple answers but the last answer is correct. When I input '.' the loop is infinite. How can I fix this?

[vb6]

isn't that what you wanted ?

[techteen143]

Originally posted by techteen143

The problem is when I input for example: 3 2 1
I get:
Answer = 8
Answer = 6
Answer = 4

and when I add the period it is infinite, what did I do wrong?

I want one answer that is correct and not knowing how many #'s will be entered I am using a while loop. And when I input a period it is supposed to stop the program instead it is in an infinite loop.
Any ideas?
Thanx

[originel]

here's the problem, when you cin the number, when you type '.', it returns it as 46.0000 because you declared a double, not a char, and whenever you enter a character, it automatically returns the ascii value ('.'=46). so you need to use some other way of ending the loop.

[vb6]

#include <iostream.h>
#include <math.h>

int main(void)
{
char choice;

double num , sum=0;
cout << "\t\t Simple Math Calculator \n\n" << endl;
cout << "select 'A' for addition, 'S' for subtraction, 'D' for division, \n";
cout << "'M' for multiplication, and 'P' for power";
cin >> choice;
if((choice == 'a') || (choice == 'A'))
{
cout << "Input numbers to be added and -1 to finish" << endl;
while(num != -1)
{
cin >> num;
if(num != -1 )
{
sum = sum + num;
}

}
}
cout << "Answer = " << sum << endl;




return 0;
}


Somthing like this ?