Ok, I'm writing a simple for loop with an accumulator for my class tonight and can't figure out what I'm doing wrong. I want the program to accept the first 10 even numbers from the keyboard and add them up and display an error message if someone enters an odd number, heres what I've got so far and the only real problem I'm having is getting the numbers to add up correctly. If some one could give me a quick response it would be great... Thanks so much.
// This program will accept and sum the first 10 even numbers as read from the keyboard.
#include <iostream>
using namespace std;
//constants
const int terminatingvalue= 10;const int two=2;const int zero=0;
int main ()
{
//Variables
int ctr=1;int num;int sum=0;
// procces
for (int ctr=1; ctr<=10; ctr++)
{
cout<<"Enter a number"<<endl;
cin>>num;
if (num%two==zero)
{
sum=sum+num;
ctr++;
}
else
cout<<"Please enter an even number"<<endl;
cout<<"Enter a number"<<endl;
cin>>num;
}
cout<<"Total is:"<<sum<<endl;
//output
return 0;
}
Last edited by thinfineline; Oct 23rd, 2008 at 5:55 pm.
My teacher said it had to be a for loop and had to declare 2 and 0 and type them out (yeah she's a little nuts). Take the second num input out worked for getting it to add correctly but now my counters off it's only accepting 6 numbers not 10.
That fixed it. I'm really sorry about the stupid questions, this is my first programming class and I'm having a really hard time with it. Thanks a bunch.
If you leave it as is, it will only perform 10 repetitions of the loop, including invalid inputs. Then you'd only get the first 10 - (number of errors) even integers in your summation. My suggestion is this:
ctr++; // only increment when a valid summation occurs
}
else
cout<<"Please enter an even number"<<endl;
cout<<"Enter a number"<<endl;
cin>>num;
}
Let me explain the for structure I used here.
for (int ctr=1; ctr<=10; )
- your original for loop incremented ctr on each run (int ctr=1; ctr<=10; ctr++)
- what I'm doing different is removing the incrementing of ctr from every run, so that
invalid numbers that are input (odds) do not count toward the number of repetitions
- this way you get 10 total numbers and not a lower number
Last edited by chococrack; Oct 23rd, 2008 at 7:36 pm.
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