easiest way to convert binary to decimal in cpp code example

Example 1: convert binary to decimal c++ stl

string bin_string = "10101010";
int number =0;
number = stoi(bin_string, 0, 2);
// number = 170

Example 2: built in function in c++ for binary to decimal

#include <bits/stdc++.h>

using namespace std;

int main(void){
    bitset<8> bits("1000");
    int ab = bits.to_ulong();
    cout << ab << "\n";
    
    return 0;
}