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Handle lack of leading zeroes and use std:19773 instead of std::rando… #41

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Handle lack of leading zeroes and use std:19773 instead of std::rando… #41

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21 changes: 16 additions & 5 deletions include/functions/random.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -23,22 +23,33 @@ const size_t MAX_RANDOM_LENGTH = 1000;
Returns a random BigInt with a specific number of digits.
*/

BigInt big_random(size_t num_digits = 0) {
std::random_device rand_generator; // true random number generator
std::random_device rd;
std::mt19937 randfunc(rd());
uint digits = uint(log10(ULLONG_MAX)) ;
std::uniform_int_distribution<unsigned long long> distribution(0, pow(10, digits) -1);

std::string rand_digits(){
unsigned long long val = distribution(randfunc);
std::string s = std::to_string(val);
for (uint len = s.length(); len < digits; len++){
s = std::string("0") + s;
}
return s;
}

BigInt big_random(size_t num_digits = 0) {
if (num_digits == 0) // the number of digits were not specified
// use a random number for it:
num_digits = 1 + rand_generator() % MAX_RANDOM_LENGTH;
num_digits = 1 + randfunc() % MAX_RANDOM_LENGTH;

BigInt big_rand;
big_rand.value = ""; // clear value to append digits
while (big_rand.value.size() < num_digits)
big_rand.value += std::to_string(rand_generator());
big_rand.value += rand_digits();
if (big_rand.value.size() != num_digits)
big_rand.value.erase(num_digits); // erase extra digits

return big_rand;
}


#endif // BIG_INT_RANDOM_FUNCTIONS_HPP