error: lvalue required as left operand of assignment

I'm trying to do some calculation program using C what am I getting error is

error: lvalue required as left operand of assignment

This error cause from define a value on the header and then I assign using = in the main body.

If I put that value which it is in the header instead put them in the int or double then it will be 开发者_JAVA技巧fine, but I don't want them to be there.

please tell me if needed more information about what I'm trying to say.

Thanks

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here is what I put on the define #define price 50

and in the body where I'm getting error price = price * 2 + total

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You can't assign to a define! After the preprocessor is done, to the compiler the code looks like this:

50 = 50 * 2 + total;

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The problem is that price is being replaced with the text 50. You can't have

50 = ...

in C. Can't do it.