将int64_t转换为double

#include<iostream>
#include <cstdint>

int main() {
    int64_t int64_value = 1234567890123456789;
    double double_value = static_cast<double>(int64_value);

    std::cout << "int64_value: "<< int64_value<< std::endl;
    std::cout << "double_value: "<< double_value<< std::endl;

    return 0;
}

int64_value: 1234567890123456789
double_value: 1.23457e+18