C++での前の数値の2進表現

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.

例

上記のアルゴリズムのプログラム実装-

#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;
}

出力

The Binary representation of the number is 1011011000
Binary representation of previous number is 1011010111