Posted on 2007-02-09 22:19
softgamer 阅读(762)
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学习日志
如果你想初始化一个类中的常量数据成员，只能用一种方法，在类的构造函数后加一个":",然后初始化那些常量数据成员，
以逗号分割。
#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