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Once again, this will generate a compile error. Although the compiler now knows how to create a Counter out of an int, it does not know how to reverse the process. |
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To solve this and similar problems, C++ provides conversion operators that can be added to your class. This enables your class to specify how to do implicit conversions to built-in types. Listing 14.9 illustrates this. One note, however: conversion operators do not specify a return value, even though they do, in effect, return a converted value. |
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LISTING 14.9 CONVERTING FROMCounterTOint() |
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1: // Listing 14.9
2: // conversion operator
3:
4: #include <iostream.h>
5:
6: class Counter
7: {
8: public:
9: Counter();
10: Counter(int val);
11: ~Counter(){}
12: int GetItsVal()const { return itsVal; }
13: void SetItsVal(int x) {itsVal = x; }
14: operator int();
15: private:
16: int itsVal;
17:
18: };
19:
20: Counter::Counter():
21: itsVal(0)
22: {}
23:
24: Counter::Counter(int val):
25: itsVal(val)
26: {}
27:
28: Counter::operator int ()
29: {
30: return ( int (itsVal) );
31: }
32:
33: int main()
34: { |
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continues |
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