在do while循环中，当前上下文中不存在名称“ dx”

Question

I have a little problem at the beggining of my code. The code is the following:

do
{
    Console.Write("x = ");
    string x = Console.ReadLine();
    double dx = Convert.ToDouble(x);
    Console.Write("X must be bigger than 1.");
}
while (dx > 1);

I want my program to ask for x, until it's bigger than 1. The problem is, at the while part of the code, I'm getting this:

The name 'dx' doesn't exist in the current context. What should I do? Or the whole code is wrong?

Answer 1

You should create dx outside loop, because variable is not visible outside { } :

double dx;
do
{
    Console.Write("x = ");
    string x = Console.ReadLine();
    dx = Convert.ToDouble(x);
    Console.Write("X must be bigger than 1.");
}
while (dx > 1);

Also, you can refactor your code a little:

double dx;
do
{
    Console.Write("x = ");
    dx = Convert.ToDouble(Console.ReadLine()); //you can get exception here if your line can't be converted to double
    Console.Write("X must be bigger than 1.");
}
while (dx > 1);