How to use Bitset to realize binary and decimal conversion

One, mutual conversion

#include <cstdio>  
#include <cmath>  
#include <cstring>  
#include < cstdlib>  
#include <string>  
#include <bitset>  
07.using namespace std;  
08.const int Size =;  
10.char str[size];  
12.int Main (void)  
13.{    int num;  
While    (~scanf ("%d", &num))///prevents negative values from being entered!  
.    {        ///into unsigned 2  
-in-system.        bitset<size> BS (num);  
strcpy (        str, bs.to_string (). C_STR ());        ///Note Log to add 1e-9  
.        for (int i = size-(int) log2 (num + 1e-9)-1; i < size; ++i)  
.            Putchar (Str[i]);        Putchar (' \ n ');  
.        Change back Method 1  
.        String str2 (str);        bitset<32> BS2 (str2);        printf ("%d\n", Bs2.to_ulong ());///or write%lud  
.        ///changed back to Method 2, #include <cstdlib>  
.        printf ("%d\n", Strtol (str, NULL, 2)); or write%ld  
.    }  
return    0;  
34.}

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Second, the generation of 0~2^k binary number

No leading 0:

#include <cstdio>  
#include <string>  
03.using namespace std;  
04.const int MAXN = 1 << 7;  
06.string BS;  
08.int Main (void)  
09.{    int i, II;    ///no leading 0  
.    for (i = 0; i < MAXN ++i)  
.    {        Ii. II = i;        bs = "";
.        {            bs = (ii & 1?) "1": "0") + BS;  
>>=-            II 1;  
.        while (ii);        puts (BS.C_STR ());  
.    return 0;  
25.}

Has a leading 0:

#include <cstdio>  
#include <string>  
#include <bitset>  
04.using namespace std ;  
05.const int Size = 4;  
06.const int MAXN = 1 << Size;  
08.int Main (void)  
09.{  
for    (int i = 0; i < MAXN ++i) one  
.    {        bitset<size> BS (i);  
Puts (        bs.to_string () c_str ());  
.    return 0;  
16.}