Error C2166: l-value specifies const object

This is a discussion on Error C2166: l-value specifies const object within the C++ Programming forums, part of the General Programming Boards category; Code: 65 int BasicMonster::calculatePower() const 66 { 67 if (weight > stamina) 68 power -= (weight - stamina) * 2; ...

  1. #1
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    Error C2166: l-value specifies const object

    Code:
     65 int BasicMonster::calculatePower() const
     
    66 {
    67 if (weight > stamina)
    68 power -= (weight - stamina) * 2;
    69 
    70 if (health <= 0)
    71 power = 0;
    72 else if (health > 100)
    73 power += (health - 100) * 3;
    74 else if (health < 10)
    75 power *= health / 10.0;
    76 
    77 return power;
    78 }

    Error 1 error C2166: l-value specifies const object 68
    Error 2 error C2166: l-value specifies const object 71
    Error 3 error C2166: l-value specifies const object 73
    Error 5 error C2166: l-value specifies const object 75


    Please, could you tell me what I have to write to not have errors?

  2. #2
    and the Hat of Guessing tabstop's Avatar
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    "const" means "constant" which means "does not change". So since you have this function marked as const (on line 65), that means you cannot change any members of the class. (In other words, if this is supposed to change some member of the class, then it cannot be a const function.)

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    Thank you!!!

  4. #4
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    if you need to change those members from inside const functions, you can mark them as mutable.

  5. #5
    C++まいる!Cをこわせ!
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    That is dangerous. You should really think it through if it makes sense to do that. For most things, it simply doesn't make sense. The only exception I can think of is thread safety.
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.

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    Elysia, I agree, but I was throwing it out there as another option that the language allows. I have never had a need to use mutable in any of my code, but I can see how it might be useful in applications like reference counting.

  7. #7
    C++まいる!Cをこわせ!
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    Not disagreeing with your reply. Just putting in a note of caution that I felt was missing.
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.

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