Thread: Having some newb troubles

Hi,
I'm trying to write a console app that will take in a base 10 number and output that number in binary form. I created a character array for the binary number and a couple of for loops (one to mod the number and divide. One to print the contents of the array.) but, I must have the syntax of something incorrect. I have looked at the code for a couple hours though and cannot figure out the issue. It seems to me when I run the app like the for loops are not even running. Anyways tia for any help.

Code:

#include <iostream>
#include <stdlib.h>

using namespace std;

int main(void) {
  int num = 0;
  int i = 0;
  //array to store the binary digits.  all values are initialized to 0.
  int binary[8] = {0};
  
  cout << "Please enter a base10 number between 0 and 255:" << endl;
  cin >> num;
  
  //loop from 7 to 0 modding the number by 2 and then dividing it in half.
  for (i = 7; i < 0; i--) {
    binary[i] = (num % 2);
    num = num / 2;
  }

  cout << "Your number is:" << endl;
  
  //loop through the binary array printing each digit.
  for (i = 0; i > 7; i++) {
    cout << binary[i];
  }
  
  cout << endl;
  	
  return 0;
}

Hi in your first for loop you have this

for (int i = 7; i < 0; i--)

and it should be this
for (int i = 7; i > -1; i--)

in the second for loop you have this

for (int i = 0; i > 7; i++)

and it should be this
for (int i = 0; i < 8; i++)

Regards William

Thanks for the fast response. I knew I was staring too hard and overlooking something silly . Thanks again.

err why would the second loop be

Code:

for (int i = 0; i < 8; i++)

when the valid array elements are 0 - 7?

Nm. Another retarded question lol. For some reason I had confused the middle argument of the for loop as the "while this condition is false" when in reality it's saying "while this condition is true". I think anyways. Thanks again for the help.

Yeah I see what your saying. I had both uses in my app and had both set backwards heh.

Originally posted by agony


You see if you are displaying 7 digits, the loop should be from 0 to 7.....

This sounds confusing; you want to do the loop 7 times, with values from 0-6. Your code itself is correct, because (i = 0; i < 7; i++) runs the loop with i = 0,1,2,3,4,5,6 (as it should).

Well it was almost correct.

Code:

#include <iostream>
#include <stdlib.h>

using namespace std;

int main(void) {
  int num = 0, num1 = 0;
  int i = 0;
  //array to store the binary digits.  all values are initialized to 0.
  int binary[8] = {0};
  cout << "Please enter a base10 number between 0 and 255:" << endl;
  cin >> num;
  
  num1 = num;
  
  //loop from 7 to 0 modding the number by 2 and then dividing it in half.
  for (i = 7; i >= 0; i--) {
      binary[i] = (num % 2);
      num = num / 2;
  }

  cout << num1 << " in binary is: ";
  
  //loop through the binary array printing each digit.
  for (i = 0; i <= 7; i++) {
    cout << binary[i];
  }
  
  cout << endl;
  
  return 0;
}

That is the correct code. Both loops had the condition of the for loop backwards. Also they had to be changed to >= and <= so the last element of the array was included. Why I could'nt figure that out I dunno, seemed like the harder I tried the further I was from getting anywhere heh. I knew the loops were'nt running but I just did'nt put 2 and 2 together. Instead I tried the "stare really hard till you find something" method.