Thread: Leading zeroes

So I had a program that made a number out of entered digits, but it doesn't work. Here's what it should print:

Code:

This program creates a number one digit at a time.
Signal the end of the number with a negative value.

Enter a number: 4
Enter a number: 11
Enter a number: 5
Enter a number: 73
Enter a number: 6
Enter a number: 24
Enter a number: -1

You entered a 3 digit number: 456

but it doesn't work.
My code is:

Code:

/*
* Create a number by entering single digits similar to a calculator.
* If numbers other than 0 thru 9 are entered they should be ignored.
* At the end, display the number of digits and the final number.
*/


#include<iostream>
using namespace std;


int main()
{
// give instructions
cout << "This program creates a number one digit at a time." << endl;
cout << "Signal the end of the number with a negative value." << endl;


int number = 0;
int cin2 = 0;
int cinvar = 0;
// PUT CHECK FOR LEADING ZEROES (ZEROES BEFORE A NUMBER)
// begin reading digits until negative entered
int count = 0;
int digit = 0;
while (true) {
cout << "Enter a number: ";
cin >> digit;
if(digit != 0) {
         cinvar++;
         }
         else {
              cin2++;
              }
if(cin2 < cinvar) {
 if (digit < 0) {
break;
}       
if (digit >= 0 && digit<=9) {
number = number + digit;
count++;


}
}
// count digits


// check to see if we are done
if (digit < 0) {
break;
}// add to our number
if (digit > 0 && digit<=9) {
number = number*10 + digit;
count++;


}


}


// final report
// count = count - 1;
cout << endl << "You entered a " << count << " digit number: " << number << endl;
}

What does your code do that's different than the expected behavior?

I would like to try my hand at helping, but I'm not sure what you're trying to achieve.

To clarify, the code is printing the wrong number of digits for some cases (but not others), and the final output has too many digits.

Originally Posted by Kelton2

To clarify, the code is printing the wrong number of digits for some cases (but not others), and the final output has too many digits.

Would you please post your output?

I only ask because I'm not going to copy and past your code, compile it and run it.

So I would replace

Code:

cin >> digit;

if (digit < 0) {
    break;
}// add to our number
if (digit >= 0 && digit<=9) {
    number = number*10 + digit;
    count++;
}

with

Code:

Code:

[COLOR=black !important]if( number == 0 && digit == 0 ) [/COLOR]
cin >> digit;

?

You would be adding code, not deleting. The changes I want you to make would allow you to do something your code couldn't before. The words in my post should make the necessary changes clear.

So I would add that if statement somewhere in that other block of code?

Right. If you understand what that if does, integrating it is easier. The topic is called "leading zeros". So, if the number is set to zero in the beginning of the program, number has not changed, and the current input is zero, we have, by induction, found a leading zero. All we do in that situation is ignore the current input.

Still not working:

Code:

/*
* Create a number by entering single digits similar to a calculator.
* If numbers other than 0 thru 9 are entered they should be ignored.
* At the end, display the number of digits and the final number.
*/
 
 
#include<iostream>
using namespace std;
 
 
int main()
{
// give instructions
cout << "This program creates a number one digit at a time." << endl;
cout << "Signal the end of the number with a negative value." << endl;
 
 
int number = 0;
int cin2 = 0;
int cinvar = 0;
// PUT CHECK FOR LEADING ZEROES (ZEROES BEFORE A NUMBER)
// begin reading digits until negative entered
int count = 0;
int digit = 0;
while (true) {
cout << "Enter a number: ";
cin >> digit;
if(digit != 0) {
         cinvar++;
         }
         else {
              cin2++;
              }
if(cin2 < cinvar) {
 if (digit < 0) {
break;
}       
if (digit >= 0 && digit<=9) {
number = number + digit;
count++;
 
 
}
}
// count digits
 
 
// check to see if we are done
if (digit < 0) {
break;
}// add to our number
if( number == 0 && digit == 0 ) 
   continue; 
if (digit > 0 && digit<=9) {
number = number*10 + digit;
count++;
 
 
}
 
 
}
 
 
// final report
// count = count - 1;
cout << endl << "You entered a " << count << " digit number: " << number << endl;
}

Actually I'm certain that the portion of code that was edited is enough to make the whole program work. Here is the output to prove it:

This program creates a number one digit at a time.
Signal the end of the number with a negative value.
Enter a number: 0
Enter a number: 0
Enter a number: 0
Enter a number: 0
Enter a number: 1
Enter a number: 21
Enter a number: 2
Enter a number: 22
Enter a number: 3
Enter a number: 56
Enter a number: 4
Enter a number: -1

You entered a 4 digit number: 1234

You are clearly working with too much code. As I said before, you need to cut the cruft.

OK, but what exactly in my program is causing it to not work? You said that you managed to make it work by implementing the same, so what's wrong in mine?