Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
Binary representation of previous number in C++
In this problem, we are given the binary representation of a number and we have to find the binary representation of the previous number i.e. the number that is resulted after subtracting one from the given number.
Binary representation of a number is changing the base of the number to base 2 and representing the number using only 0 or 1.
For example, Binary representation of 23 is 10111.
So, here we would be given a number, let's say n in binary form. And we have to find the binary representation of n-1.
To solve this problem, we need to know the basics of binary subtraction. let's see what happens when 1 is subtracted from 0 or 1 in binary form.0 - 1 = 1 + 1 carry from next bit. 1 - 1 = 0.
Let's take an example to understand the problem better,
Input : 101101100 Output : 101101011 Explanation : (101101100)2 Is the binary representation of 364. The number preceding it is 363 whose binary representation is (101101011)2 . we have used binary subtraction here and subtracted (1)2 from the binary representation of the number to yield the result .
Let's see the logic behind this program and then we will design an algorithm based on our logic. Here we need to subtract one from the number’s binary representation. for this, we will start from the right and flip all zeros to 1 until, 1 is encountered. When 1 is encountered, we will flip the 1 to 0 and return the final result.
Algorithm
Step 1 : Start right to left i.e n-1 to 0. Step 2 : If 1 is encounter change it to 0 and break. Step 3 : If 0 is encountered, change it 1. Step 4 : Print the array.
Example
Program implementation of the above algorithm −
#include <bits/stdc++.h>
using namespace std;
string previousNumber(string num) {
int n = num.size();
if (num.compare("1") == 0)
return "0";
int i;
for (i = n - 1; i >= 0; i--) {
if (num.at(i) == '1') {
num.at(i) = '0';
break;
} else
num.at(i) = '1';
}
if (i == 0)
return num.substr(1, n - 1);
return num;
}
int main() {
string number = "1011011000";
cout<<"the Binary representation of the number is "<<number<<endl;
cout<<"Binary representation of previous number is "<<previousNumber(number);
return 0;
}Output
The Binary representation of the number is 1011011000 Binary representation of previous number is 1011010111
214 Views
