How to find all 4 digits numbers that are palindrome in base 10 and base 2 with C++

1 Answer

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#include <algorithm>
#include <iostream>
#include <bitset>

std::string toBinary(int num) {
    std::string binary = std::bitset<16>(num).to_string(); 
    binary.erase(0, binary.find_first_not_of('0'));
    
    return binary;
}
   
bool isBinaryRepresentationOfNumberPalindrome(unsigned int num) {
    std::string binary = std::bitset<16>(num).to_string(); 
    binary.erase(0, binary.find_first_not_of('0'));
 
    std::string reversebinary = binary;
    std::reverse(reversebinary.begin(), reversebinary.end());
    
    return binary == reversebinary;
}
 
bool isPalindrome(int n) {
    int reverse = 0, temp = n;
  
    while (temp != 0) {
        int remainder = temp % 10;
        reverse = (reverse * 10) + remainder;
        temp = temp / 10;
    }
  
    return n == reverse;
}
   
int main()
{
    for (int i = 1000; i < 10000; i++) {
        if (isPalindrome(i) && isBinaryRepresentationOfNumberPalindrome(i)) {
            std::cout << i << " " << toBinary(i) << "\n";
        }
    }
}
  
     
     
/*
run:
  
7447 1110100010111
9009 10001100110001
  
*/

 



answered Jan 9, 2024 by avibootz
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