What are the 1's complement and 2's complement of binary numbers?

Binary numbers are represented in base 2. It only uses the two digits "0" and "1". Each digit in a binary number is a bit.

Example binary number - 0100010111

1's complement number

The binary number's complement number is by reversing the digits of the binary number, that is, 1 is converted to 0, and 0 is converted is obtained as 1.

Example

1’s Complement of 101100 = 010011

2's complement

The complement of a binary number is the complement of the binary number plus 1, that is, 1's complement of 1.

Example

2’s complement of 101101 is 010011.

Sample code

Code to find one and two's complement -

#include <iostream>
#include<string.h>
using namespace std;
int main() {
   char binary[10] = "01001011";
   cout<<&ldquo;Binary number is &rdquo;<<binary;
   //once complement....
   int length = strlen(binary);
   for(int i=0;i<length;i++) {
      if(binary[i] == &#39;0&#39;) {
         binary[i]= &#39;1&#39;;
      } else
         binary[i] = &#39;0&#39;;
   }
   cout<<&ldquo;One&rsquo;s Complement is &rdquo;<<binary<<endl;
   // cout<<binary[length-1];
   for(int i = length-1; i>=0; i--) {
      // cout<<binary[i];
      if(binary[i] == &#39;0&#39;) {
         binary[i] = &#39;1&#39;;
         //cout<<binary[i];
         break;
      } else {
         binary[i] = &#39;0&#39;;
      }
   }
   cout<<&ldquo;Two&rsquo;s complement is &rdquo;<<binary;
   return 0;
}

Output

Binary number is 01001011
One’s complement is 10110100
Two’s complement is 10110101

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