Fastest way to convert binary to decimal?

Question

I\'ve got four unsigned 32-bit integers representing an unsigned 128-bit integer, in little endian order:

typedef struct {
    unsigned int part[4];
} bigint         


        

Answer 1

I know this question is old, but I want to contribute as none put a way avoiding the division cycle. This one uses pow2, I haven't tested the benchmark but in theory should be faster than any other, and also could be tweaked in the pow function as well.

#include 
#include 
using namespace std;

#define MathBintodec(arr,len)({int dec=0;int ci_;for(ci_=len;ci_--;)dec+=arr[ci_]*pow(2,len-ci_-1);dec;})

int main(){
    int r[]={1,0,0,1,0,0};
    cout<

Output: 36