将字符串转换为double

#include<string>
#include<iostream>

int main() {
    std::string str = "3.1415926";
    double num = std::stod(str);
    std::cout << "The double value is: "<< num<< std::endl;
    return 0;
}

str = "3.1415926"
num = float(str)
print("The double value is:", num)

public class Main {
    public static void main(String[] args) {
        String str = "3.1415926";
        double num = Double.parseDouble(str);
        System.out.println("The double value is: " + num);
    }
}

let str = "3.1415926";
let num = parseFloat(str);
console.log("The double value is:", num);