////  main.cpp//  2_1////  Created by T.P on 2018/2/28.//  Copyright © 2018年 T.P. All rights reserved.//#include 
    
     #include 
     
      using namespace std;int main() {    cout<<"Hello!"<
      
       =60? "pass":"fail")<
       
        <
       
      
     
    

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////  main.cpp//  2_2////  Created by T.P on 2018/3/4.//  Copyright © 2018年 T.P. All rights reserved.////判断闰年//:闰年可以被4整除而不能被100整除，或者能被400整除。//表达式((year%4==0&&year%100!=0)||(year%400==0))#include 
    
     #include 
     
            //包含IO类库操作符using namespace std;    //没写 using namespace std; 用 std::cout                        //写了 using namespace std; 用 cout 就可以了。int main(int argc, const char * argv[]) {    // insert code here...    //std::cout << "Hello, World!\n";    int year;    bool isLeapYear;        cout<<"Enter the year:";    cin>>year;    isLeapYear=((year%4==0&&year%100!=0)||(year%400==0));        if(isLeapYear)        cout<
      
       <<"is a leap year"<
      
     
    

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////  main.cpp//  2_3////  Created by T.P on 2018/3/4.//  Copyright © 2018年 T.P. All rights reserved.////比较两个数的大小#include 
    
     #include 
     
      using namespace std;int main(int argc, const char * argv[]) {    int x,y;    cout<<"Please Enter x and y : ";    cin>>x>>y;    cout<
      
       y)            cout << "x>y";        else            cout << "x
      
     
    

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////  main.cpp//  2_4////  Created by T.P on 2018/3/4.//  Copyright © 2018年 T.P. All rights reserved.////输入一个0~6的整数，转换成星期输出#include 
    
     #include 
     
      using namespace std;int main(int argc, const char * argv[]) {    // insert code here...    //std::cout << "Hello, World!\n";    int day;    cin>>day;    switch (day) {        case 0:            cout<<"Sunday";            break;        case 1:            cout<<"Monday";            break;        case 2:            cout<<"Tuesday";            break;        case 3:            cout<<"Wednesday";            break;        case 4:            cout<<"thursday";            break;        case 5:            cout<<"Friday";            break;        case 6:            cout<<"Saturday";            break;        default:            cout<<"Day out of range Sunday...Saturday";            break;    }    cout<