C++学习day4

思维导图：

练习：

#include <iostream>
#include <cstring>
#include <cstdlib>
#include <unistd.h>
#include <sstream>
#include <vector>
#include <memory>

using namespace std;

class mydouble{
private:

    int a;
    int b;
public:

    mydouble(int a,int b):a(a),b(b){};
    void show()
    {
        cout << a << "." << abs(b) << endl;
    }
    mydouble operator+(const mydouble& r)
    {
        mydouble AB(0,0);
        AB.a= a + r.a;
        AB.b= b + r.b;                                       
        return AB;
    }

    mydouble operator-(const mydouble& r)
    {
        mydouble AB2(0,0);
        AB2.a = a - r.a;
        AB2.b = b - r.b;
        return AB2;
    }

    mydouble operator*(const mydouble& r)
    {
        mydouble AB3(0,0);
        AB3.a = a * r.a;
        AB3.b = b * r.b;
        return AB3;
    }


};

int main(int argc,const char** argv){
    mydouble A(3,14);
    A.show();
    mydouble B(1,23);
    B.show();

    mydouble AB=A+B;
    printf("A+B的值为：");
    AB.show();

    mydouble AB2 = A-B;
    printf("A-B的值为：");
    AB2.show();

    mydouble AB3 = A*B;
    printf("A*B的值为：");
    AB3.show();

}
                                                             

#include <iostream>
#include <cstring>
#include <cstdlib>
#include <unistd.h>
#include <sstream>
#include <vector>
#include <memory>

using namespace std;

class myOut{
private:

public:
    void operator<<(int a)
    {
        printf("%d\n",a);
        cout<<a<<endl;
    }
    void operator<<(double a )
    {
        printf("%f\n",a);
        cout<<a<<endl;
    }
    void operator<<(const char* a)
    {
        printf("%s\n",a);
        cout<<a<<endl;                                          
    }
    void operator<<(ostream&(*endl)(ostream&))
    {
        printf("\n");
    }
};
/*ostream& operator<<(ostream& out,const myOut& r)
{
    out<<r;
*/
int main(int argc,const char** argv){

    myOut out;
    out<<1;
    out<<3.14;
    out<<"hello";
    out<<endl;
    return 0;
}