# 1’s and 2’s complement of a Binary Number?

Binary Number is expressed in base 2. It uses only two digits ‘0’ and ‘1’. Each digit in a binary number is a bit.

Sample binary Number − 0100010111

## 1’s Complement

One's complement of a binary number is obtained by reversing the digits of the binary number i.e. transforming 1 with 0 and 0 with 1.

## Example

1’s Complement of 101100 = 010011

## 2’s Complement

Two’s complement of a binary number is obtained by adding one to the one’s complement of a binary number i.e. 1’s complement + 1.

## Example

2’s complement of 101101 is 010011.

## Example Code

Code to find One’s and two’s complement −

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

## Output

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

karthikeya Boyini

I love programming (: That's all I know

Updated on: 30-Jul-2019

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