程序设计与算法（三）第七周测验(2018春季)

题目网址：http://cxsjsxmooc.openjudge.cn/2018t3springw7/

【1:简单的SumArray】

#include <iostream>
#include <string>
using namespace std;
template <class T>
T SumArray(
T* s,T* e){
 T tmp=*s;
 for(T* i=s+1;i<e;i++){
     tmp+=*i;
 }
 return tmp;
}
int main() {
    string array[4] = { "Tom","Jack","Mary","John"};
    cout << SumArray(array,array+4) << endl;
    int a[4] = { 1, 2, 3, 4};  //提示：1+2+3+4 = 10
    cout << SumArray(a,a+4) << endl;
    return 0;
}

【2:简单的foreach】

 

#include <iostream>
#include <string>
using namespace std;
template<class T1,class T2>
void MyForeach(T1 begin,T1 end,T2 op){
    for(T1 i=begin;i<end;i++){
        op(*i);
    }
}
void Print(string s)
{
    cout << s;
}
void Inc(int & n)
{
    ++ n;
}
string array[100];
int a[100];
int main() {
    int m,n;
    while(cin >> m >> n) {
        for(int i = 0;i < m; ++i)
            cin >> array[i];
        for(int j = 0; j < n; ++j)
            cin >> a[j];
        MyForeach(array,array+m,Print);         
        cout << endl;
        MyForeach(a,a+n,Inc);         
        for(int i = 0;i < n; ++i)
            cout << a[i] << ",";
        cout << endl;
    }
    return 0;
}

 

【3:简单的Filter】

 

#include <iostream>
#include <string>
using namespace std;
template<class T1,class T2>
T1 Filter(T1 begin,T1 end ,T1 arr,T2 op){
    int index=0;
    for(T1 i=begin;i<end;i++){
        if(op(*i)){
            arr[index++]=*i;
        }
    }
    return (arr+index);
}
bool LargerThan2(int n)
{
    return n > 2;
}
bool LongerThan3(string s) 
{
    return s.length() > 3;
}

string as1[5] = {"Tom","Mike","Jack","Ted","Lucy"};
string as2[5];
int  a1[5] = { 1,2,3,4,5};
int a2[5];
int main() {
    string * p = Filter(as1,as1+5,as2,LongerThan3);
    for(int i = 0;i < p - as2; ++i)
        cout << as2[i];
    cout << endl; 
    int * p2 = Filter(a1,a1+5,a2,LargerThan2);
    for(int i = 0;i < p2-a2; ++i)
        cout << a2[i] << ",";
    return 0;
}

 

【4:你真的搞清楚为啥 while(cin >> n) 能成立了吗？】

#include <iostream>
using namespace std;
class MyCin
{
public:
    int flag;
    MyCin():flag(0){
    }
istream& operator >>(int& x){
    cin>>x;
    if(x==-1)
    exit(0);
    return cin;
}

};
int main()
{
    MyCin m;
    int n1,n2;
    while( m >> n1 >> n2) 
        cout  << n1 << " " << n2 << endl;
    return 0;
}

 

【5:山寨版istream_iterator】

#include <iostream>
#include <string>

using namespace std;
template <class T>
class CMyistream_iterator
{
public:
    T value;
CMyistream_iterator(istream& i){
    i>>value;
}
void operator ++(int){
    cin>>value;
}
T operator *(){
    return value;
}
};



int main()  
{ 
    int t;
    cin >> t;
    while( t -- ) {
         CMyistream_iterator<int> inputInt(cin);
         int n1,n2,n3;
         n1 = * inputInt; //读入 n1
         int tmp = * inputInt;
         cout << tmp << endl;
         inputInt ++;   
         n2 = * inputInt; //读入 n2
         inputInt ++;
         n3 = * inputInt; //读入 n3
         cout << n1 << " " << n2<< " " << n3 << " ";
         CMyistream_iterator<string> inputStr(cin);
         string s1,s2;
         s1 = * inputStr;
         inputStr ++;
         s2 = * inputStr;
         cout << s1 << " " << s2 << endl;
    }
     return 0;  
}

【6:这个模板并不难】

#include <iostream>
#include <string>
#include <cstring>
using namespace std;
template <class T>  
class myclass {
public:
    T* p;
    int size;
    myclass(T* arr,int n){
        size=n;
        p=new T[n];
        for(int i=0;i<n;i++){
            p[i]=arr[i];
        }
    }
~myclass( ) {
        delete [] p;
    }
    void Show()
    {
        for( int i = 0;i < size;i ++ ) {
            cout << p[i] << ",";
        }
        cout << endl;
    }
};
int a[100];
int main() {
    char line[100];
    while( cin >> line ) {
        myclass<char> obj(line,strlen(line));;
        obj.Show();
        int n;
        cin >> n;
        for(int i = 0;i < n; ++i)
            cin >> a[i];
        myclass<int> obj2(a,n);
        obj2.Show();
    }
    return 0;
}

【7:排序，又见排序!】

#include <iostream>
using namespace std;

bool Greater2(int n1,int n2) 
{
    return n1 > n2;
}
bool Greater1(int n1,int n2) 
{
    return n1 < n2;
}
bool Greater3(double d1,double d2)
{
    return d1 < d2;
}

template <class T1,class T2>
void mysort(
T1 begin,T1 end,T2 op){
    T1 i,j;
    for( i=begin;i<end;i++){
        for( j=i+1;j<end;j++){
            if(!op(*i,*j)){
                *i=*i+*j;
                *j=*i-*j;
                *i=*i-*j;
            }
        }
    }
}
#define NUM 5
int main()
{
    int an[NUM] = { 8,123,11,10,4 };
    mysort(an,an+NUM,Greater1); //从小到大排序 
    for( int i = 0;i < NUM; i ++ )
       cout << an[i] << ",";
    mysort(an,an+NUM,Greater2); //从大到小排序 
    cout << endl;
    for( int i = 0;i < NUM; i ++ )
        cout << an[i] << ","; 
    cout << endl;
    double d[6] = { 1.4,1.8,3.2,1.2,3.1,2.1};
    mysort(d+1,d+5,Greater3); //将数组从下标1到下标4从小到大排序 
    for( int i = 0;i < 6; i ++ )
         cout << d[i] << ","; 
    return 0;
}