C++ 臨時測驗

Define:
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) v" H9 T/ \+ l9 I2 u7 c# hconst int x = 17;
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public:
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6 R  ^$ J# T. ^   A(int n);
: I" I  Y& I) `  v& x   int f() const;& c  B+ Z1 G- r' J% l3 h+ q
   int g(const A& x);
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};
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Each of the three const keywords is a promise to the compiler that the compiler will enforce.
, v3 z  A  c& k2 r" |What is the promise in each case?