convert from string to double !

I got a string that contains numbers let's say "1.54251"
I want to convert this string to double because I want to do some operations on that number
I tried normal casting but didn't work.
I remember something about type_cast but I can't get it to work.

Can anyone help me with this ?
Thanks.

EDIT: I tried this

Quote:

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static_cast<double>(var);

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and I got this
Error 1 error C2440: 'static_cast' : cannot convert from 'std::string' to 'double'

You don't type cast strings (or character arrays) containing numeric digits directly into ints or doubles. You need to convert them using other means... usually using something like stringstreams, sscanf, or one of the many functions available that do such things (strtod as an example).

OK I searched MSDN library for the strtod and I found a program but I can't understand this part.

Quote:

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string = "3.1415926This stopped it";
x = strtod( string, &stopstring );

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How does it work ?
and what if the text is at the beginning of the string ?

It worked for me btw thanks a lot.

3.1415926 is what the double will contain.
"This stopped it" just shows that when a non-numeric character comes, it just stops converting.

In &stopstring you are passing the address to a pointer to char that will store the address where the conversion has ended. In your example this will return the address of "T".