Question

I have 2 arrays (both containing 2 strings each) one contains serial numbers from a USB. the other contains serial numbers from a text file. I was able to retrieve them both successfully. So here’s my problem: I need to compare them to each other, find exactly one serial number that differs, and replace it. like this:

Contents (Dummy Serial numbers)
     ________
USB | A | B

TXT | B | C

As you can see, the USB and TXT array both contain one of the same serial number (B). That part is easy; I however need to write code to see that C != A and then I need A to replace C.

I tried this:

for (int x = 0; x < 2; x++)
{
     for (int y = 0; y < 2; y++)
     {
          //checks for same serial number
          if (m_AttachedUSB[x] == m_Existing_Serial_Numbers[y])
          {
              //found one
              IntOnlyOne++;
              //we want this one to stay beacause it has a serial number 
              //that matches one in the .txt file
              m_ChachedUSB = m_AttachedUSB[x];
          }
     }
}

This however only finds the serial numbers that are similar. How do I replace the ones that are different?

Answer 1

With only 4 items in your lists you can keep it simple:

if(usbArray[0] == textArray[0])
  usbArray[1] = textArray[1];
else if(usbArray[0] == textArray[1])
  usbArray[1] = textArray[0];
else if(usbArray[1] == textArray[0])
  usbArray[0] = textArray[1];
else if(usbArray[1] == textArray[1])
  usbArray[0] = textArray[0];

Basically, change the two that are different.

And a second solution:

for(int i=0; i<=1; i++)
  for(int j=0; j<=1; j++)
     if(usbArray[i] == textArray[j])
       usbArray[(i+1)%2] = textArray[(j+1)%2];