6月24日代码

#include<iostream>
using namespace std;
template<typename T>
void swap(T &a,T &b)
{
    T temp=a;
    a=b;
    b=temp;
}
int main()
{
    double dx=3.5,dy=5.6;
    int ix=6,iy=7,ia=303,ib=505;
    string s1="good",s2="better";
    cout<<"double dx="<<dx<<",     dy="<<dy<<"
";
    cout<<"int    ix="<<ix<<",     iy="<<iy<<"
";
    cout<<"string s1=""<<s1<<"",   s2=""<<s2<<""
";
    swap(dx,dy);
    swap(ix,iy);
    swap(s1,s2);
    swap(ia,ib);
    cout<<"
after swap:
";
    cout<<"double dx="<<dx<<",    dy="<<dy<<"
";
    cout<<"int   ix="<<ix<<",      iy="<<iy<<"
";
    cout<<"string s1=""<<s1<<"",s2=""<<s2<<""
";
}

template<typename T>
void swap(T &a,T &b)
{
    T temp=a;
    a=b;
    b=temp;
}
int add(double a,double b)
{
    return a+b;
}
int main()
{
    int ia=3;
    double db=5.0;
    char s1[]="good",s2[]="better";
    int x=add(ia,db);
    /*swap(ia,db);
    swap(s1,s2);*/
}
//-------------------
template<typename T>
T max(T a,T b)
{
    return a<b?b:a;
}
//const T&a与T const&a等价
//----------------------------------------
#include<iostream>
template<typename T>
T const& max(T const& a,T const& b)
{
    return a<b?b:a;
}
int main()
{
    int ia=3;
    double db=5.0;
    std::cout<<max<double>(ia,db)<<"
";
    std::cout<<max(static_cast<double>(ia),db)<<"
";
}
//--------------------------------------------
#include<iostream>
template<typename T>
void swap(T &a,T&b)
{
    T temp=a;
    a=b;
    b=temp;
}
int main()
{
    int ia=3;
    const int cb=5;
    swap(ia,7);
    swap<int>(ia,7);
    swap(cb,7);
    swap<const int>(ia,7);
}
//----------------
const char*const& max(const char*const&a,const char* const&b)
{
    return std::strcmp(a,b)<0?b:a;
}
//------------------
void f(int *ix,int *iy,double *dx,double *dy)
{
    int *ip=max(ix,iy);
    double *dp=max(dx,dy);
}
//-----------------------------------
#include<iostream>
template<typename T>
T const& max(T const&a,T const&b)
{
    return a<b?b:a;
}
template<typename T>
T*const& max(T*const&a,T*const&b)
{
    return *a<*b?b:a;
}
const char*const&max(const char* const&a,const char*const&b)
{
    return std::strcmp(a,b)<0?b:a;
}
int main()
{
    int ia=3,ib=7;
    char*s1="hello";
    char*s2="hell";
    std::cout<<*max(&ia,&ib)<<"
";
    std::cout<<max(s1,s2)<<"
";
    std::cout<<max(ia,ib)<<"
";
}

#include<iostream>
using namespace std;
int main()
{
    int score;
    int factor;
    char grade;
    cout<<"请输入一个0到100之间的整数，-1表示输入结束："<<endl;
    cin>>score;
    while(score!=-1)
    {
        if(score>100||score<0)
        {
            cout<<"输入错误，请输入一个0到100之间的整数，-1表示输入结束："<<endl;
            cin>>score;
        }
        else
        {
            factor=score/10;
            switch (factor)
            {
            case 10:
            case 9:grade='A';break;
            case 8:grade='B';break;
            case 7:grade='C';break;
            case 6:grade='D';break;
            default:grade='E';
                break;
            }
            cout<<score<<"对应的分数等级为："<<grade<<endl;
            cout<<"请输入一个0到100之间的整数，-1表示结束："<<endl;
            cin>>score;
        }
    }
    if(score=-1)
        cout<<"输入结束！"<<endl;
    return 0;
}

#include<iostream>
using namespace std;
int main()
{
    int peachs=1;
    for(int i=1;i<10;i++)
    {
        peachs=(peachs+1)*2;
        cout<<"第"<<10-i<<"天桃子的个数为"<<peachs<<endl;
    }
    return 0;
}

#include<iostream>
using namespace std;
int main()
{
    const int n=8;
    int a[n]={0,0,0,0,0,0,0,0};
    int b[n]={0,0,0,0,0,0,0,0};
    int change;
    double average;
    int k,temp,sum=0;
    cout<<"请输入8个整数
";
    for(k=0;k<n;k++)
    {
        cin>>a[k];
        sum+=a[k];
    }
    
    cout<<"原始的输入为：
";
    for(k=0;k<n;k++)
        cout<<a[k]<<" ";
    cout<<endl;

    average=sum/8;
    cout<<"输入的平均值为："<<average<<endl;

    change=n/2;
    for(k=0;k<change;k++)//方法
    {
        temp=a[k];
        a[k]=a[n-1-k];
        a[n-1-k]=temp;
    }
    cout<<"该数组的逆序输出为：
";
    for(k=0;k<n;k++)
        cout<<a[k]<<" ";
    cout<<"逆序输出结束："<<endl;
    for(int mm=0;mm<n-1;mm++)
    {
        for(int nn=mm;nn<=n-1;nn++)
        if(a[mm]<a[nn+1])
        {
            temp=a[mm];
            a[mm]=a[nn+1];
            a[nn+1]=temp;
        }
    }
    cout<<"该数组从大到小排序后输出：
";
    for(k=0;k<n;k++)
        cout<<a[k]<<" ";
    cout<<endl;
    int i=0;
    int j=0;
    cout<<"删除数组中重复元素后的，新数组为："<<endl;
    while(i<n)
    {
        b[j]=a[i];
        cout<<b[j]<<" ";
        i++;
        j++;
        while(a[i-1]==a[i])
            i++;
    }
    cout<<endl;
    return 0;
}

#include<iostream>
#include<fstream>
#include<iomanip>
using namespace std;

int main()
{
    ifstream in("a.txt");
    double a[5][5]={0};
    double sum=0;
    cout<<"导入的矩阵：
";
    for(int i=0;i<5;i++)
    {
        for(int j=0;j<5;j++)
        {
            in>>a[i][j];
            cout<<setw(3)<<a[i][j];
            if((i==j)||(i+j==4))
            {
                sum+=a[i][j];
            }
        }
        cout<<endl;
    }
        cout<<"nnj:"<<sum<<endl;
        return 0;
}