Posted on 2007-02-09 22:19
softgamer 閱讀(765)
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學習日志
如果你想初始化一個類中的常量數據成員，只能用一種方法，在類的構造函數后加一個":",然后初始化那些常量數據成員，
以逗號分割。
#include <iostream>
using std::cout;
using std::endl;
class Test
{
? public:
??? Test(int i = 0, int j = 1 );
??? void addon() { count += idx; }
??? void print() const;
? private:
??? int count;
??? const int idx;
?? ?const int idy;
};
Test::Test( int i, int j )
? :idx( j, i ), idy( j, j )
{
?? count = j;
}
void Test::print() const
{
?? cout << "count= " << count
??????? <<", idx = " << idx
?? ???? <<", idy = " << idy
?? ???? << endl;
}
int main()
{
??? Test Test1( 20, 7 );
??? cout << "Before doing addon: ";
??? Test1.print();
??? for ( int k = 0; k < 3; k++ )
??? {
?????? Test1.addon();
?????? cout << "After addon " << k + 1 << ":";
?????? Test1.print();
??? }
??? return 0;
}
result:
Before doing addon: count= 7, idx = 20, idy = 7
After addon 1:count= 27, idx = 20, idy = 7
After addon 2:count= 47, idx = 20, idy = 7
After addon 3:count= 67, idx = 20, idy = 7