C++ convert binary to decimal for bit values greater than 64 bits -

i using code convert binary decimal. code not work more 64 bits __int64 holds 8 bytes. please tell suggest algorithm use convert more 64 bits decimal values. end result has string. appreciated. thanks.

 int bin2dec(char *bin)  {     __int64  b, k, m, n;     __int64  len, sum = 0;      len = strlen(bin) - 1;     for(k = 0; k <= len; k++)     {             n = (bin[k] - '0'); // char numeric value             if ((n > 1) || (n < 0))             {                     puts("\n\n error! binary has 1 , 0!\n");                     return (0);             }             for(b = 1, m = len; m > k; m--)             {                     // 1 2 4 8 16 32 64 ... place-values, reversed here                     b *= 2;             }             // sum             sum = sum + n * b;     }     return(sum);  } 

typically, when dealing data bigger can store in 1 integer unit, solution 1 of 2 things:

1. use character array/string store value "ascii" (in 1 bit per char)
2. use multiple integers in array store values, using x bits per element.

there nothing particularly different conversion, once have done x bits, shift next element.

by way:

int bin2dec(char *bin)  {     int  k, n;     int len;     __int64  sum = 0;      len = strlen(bin);     for(k = 0; k < len; k++)     {             n = (bin[k] - '0'); // char numeric value             if ((n > 1) || (n < 0))             {                     puts("\n\n error! binary has 1 , 0!\n");                     return (0);             }             // sum             sum <<= 1;             sub += n;     }     return(sum);  } 

is bit simpler.