C++练习题

 class myDouble{
 private:
     int 整数部分a
     int 小数部分b
 public:
     myDouble(int a,int b):a(a),b(b){}    
     void show(){
         cout << a << "." << abs(b) << endl;     
     }           
 }
 
 myDouble x(3,14)
 x.show() 终端上输出 3.14
 
 要求实现 myDouble的
 operator+
 operator-
 operator*

#include <iostream>
#include <cstring>
#include <cstdlib>
#include <unistd.h>
#include <sstream>
#include <vector>
#include <memory>
#include <math.h>
using namespace std;
 
class myDouble{
	private:
		int a;
		int b;
	public:
		myDouble(int a=0,int b=0):a(a),b(b){}
 
		void show()
		{
			cout <<a<<"."<<abs(b)<<endl;
		}
		myDouble operator+(const myDouble& r){
			myDouble temp;
			temp.a=this->a+r.a;
			temp.b=this->b+r.b;
			return temp;
		}	
 
		myDouble operator-(const myDouble& r){    
			myDouble temp;
			temp.a=this->a-r.a;
			temp.b=this->b-r.b;
			return temp;
		}   
		/*
		   myDouble operator*(const myDouble& r){    
		   myDouble temp;
		   int ten=0,sum=0,count=0,count1=0,count2=0;
		   int m=this->b,n=r.b;
		   while(m/10!=0){count1++;m/=10;}
		   while(n/10!=0){count2++;n/=10;}
		   sum=(pow(10,count1)*this->a+this->b)*(pow(10,count2)*r.a+r.b);
		   count=count1+count2;
		   ten=pow(10,count);
		   temp.a=sum/ten;
		   temp.b=sum%ten;
		   return temp;
		   }   
		   */
		myDouble operator*(const myDouble& r) {
			myDouble temp(0, 0);
			int count1 = countdi(this->b);  // this->b的小数位数
			int count2 = countdi(r.b);      // r.b的小数位数
			long long sum = (long long)(this->a * pow(10, count1) + this->b) * (long long)(r.a * pow(10, count2) + r.b);
			int count = count1 + count2;
			temp.a = sum / pow(10, count);
			temp.b = sum % (int)pow(10, count);
			return temp;
		}
		int countdi(int num) {
			int count = 0;
			if (num == 0) {
				return 1;  // 特殊情况：0有1位
			}
			while (num != 0) {
				num /= 10;  // 每次将数字除以10，直到它变为0
				count++;    // 每除一次，位数增加1
			}
			return count;
		}
};
 
int main(int argc,const char** argv){
	myDouble x(3,14);
	myDouble y(2,41);
	
	myDouble a=x+y;
	myDouble b=x-y;

	a.show();
	b.show();
	myDouble z=x*y;
	z.show();
}

 class myOut{
     没有私有成员
     只有公开函数   
}
myOut out;
out << 1     终端输出1
out << 3.14  终端输出3.14
out << "hello" XXXXX
最有难度的: out << endl 终端输出换行符
不允许使用 cout 去做,用printf 去做

#include <iostream>
#include <cstring>
#include <cstdlib>
#include <unistd.h>
#include <sstream>
#include <vector>
#include <memory>
#include <math.h>
using namespace std;
 
class myOut{
    private:
	public:
		myOut(){}
		myOut& operator<<(const int&value){    
			printf("%d",value);
			return *this;
		}   
 
		myOut& operator<<(const double&value){    
			printf("%f",value);
			return *this;
		}   
		myOut& operator<<(const char*value){    
			printf("%s",value);
			return *this;
		}   
		myOut& operator<<(const myOut&(myOut&)) {
			return manip(*this);
		}
 
 
 
};
myOut out;
myOut endl(myOut& out)
{
	printf("\n");
	return out;
}
int main(int argc,const char** argv){
	out<<1;
	out<<3.14;
	out<<"1111";
	out<<endl;
}