几种著名算法实现总结

[c++]代码库

/*
用数组处理Fibonacci问题
*/
#include <iostream>
#include <iomanip>
using namespace std;
int main()
{
    int i;
    int f[20]={1,1};
    for(i=2;i<20;i++)
        f[i]=f[i-2]+f[i-1];
    for(i=0;i<20;i++)
    {
        if(i%5==0)  cout<<endl;
          cout<<setw(8)<<f[i];
    }
    cout<<endl;
    return 0;
}
 
/*
用逻辑表达式求解闰年
*/
#include <iostream>
using namespace std;
int main()
{
    int year;
    bool leap;
    cout<<"please enter year:";
    cin>>year;
    if((year%4==0&&year%100!=0)||year%400==0)
       leap=true;
    else
        leap=false;
     
    if(leap)
        cout<<year<<" is ";
    else
        cout<<year<<" is not ";
    cout<<"a leap year."<<endl;
    return 0;
}
 
/*
用布尔变量prime求素数
*/
#include <iostream>
#include <cmath>
#include <iomanip>
using namespace std;
int main()
{
    int m,k,i,n=0;
    bool prime;
    for(m=1;m<=1000;m=m+2)
    {
        prime=true;
        k=int(sqrt(m));
        for(i=2;i<=k;i++)
            if(m%i==0)
            {
                prime=false;
                break;
            }
            if(prime)
            {
                cout<<setw(5)<<m;
                n=n+1;
            }
            if(n%10==0) cout<<endl;
    }
    cout<<endl;
    return 0;
}
 
/*
用布尔变量leap求解闰年
*/
#include <iostream>
using namespace std;
int main()
{
    int year;
    bool leap;
    cout<<"please enter year:";
    cin>>year;
    if(year%4==0)
    {
        if(year%100==0)
    {
            if(year%400==0)
                   leap=true;
            else leap=false;}
        else
         leap=true;}
    else
         leap=false;
    if(leap)
        cout<<year<<" is ";
    else
        cout<<year<<" is not ";
    cout<<"a leap year."<<endl;
    return 0;
}
 
/*
选择法排序一组数
*/
#include <iostream>
using namespace std;
int main()
{
    void select_sort(int array[],int n);
    int a[10],i;
    cout<<"enter the originl aray:"<<endl;
    for(i=0;i<10;i++)
        cin>>a[i];
    cout<<endl;
    select_sort(a,10);
    cout<<"the sorted array:"<<endl;
    for(i=0;i<10;i++)
        cout<<a[i]<<" ";
    cout<<endl;
    return 0;
}
 
 
void select_sort(int array[],int n)
{
    int i,j,k,t;
    for(i=0;i<n-i;i++)
    {
        k=i;
        for(j=i+1;j<n;j++)
            if(array[j]<array[k])  k=j;
            t=array[k];array[k]=array[i];array[i]=t;
    }
}
 
/*
统计一篇文章中各字符个数
*/
#include <iostream>
using namespace std;
int main()
{
    int i,j,upper,lower,digit,space,others;
    char text[3][80];
    upper=lower=digit=space=others=0;
    for(i=0;i<3;i++)
    {
        cout<<"please input line"<<i+1<<endl;
        gets(text[i]);
        for(j=0;j<80&&text[i][j]!='\0';j++)
        {
            if(text[i][j]>='A'&&text[i][j]<='Z')
                upper++;
            else if(text[i][j]>='a'&&text[i][j]<='z')
                lower++;
            else if(text[i][j]>='0'&&text[i][j]<='9')
                digit++;
            else if(text[i][j]==' ')
                space++;
            else
                others++;
        }
    }
    cout<<"upper case:"<<upper<<endl;
    cout<<"lower case:"<<lower<<endl;
    cout<<"digit     :"<<digit<<endl;
    cout<<"space     :"<<space<<endl;
    cout<<"others    :"<<others<<endl;
    return 0;
}
 
/*
打擂台法求矩阵中最大元素及其行列号
*/
#include <iostream>
using namespace std;
int main()
{
    int i,j,row=0,colum=0,max;
    int a[3][4]={{5,12,23,56},{19,28,37,46},{-12,-34,6,8}};
    max=a[0][0];
    for(i=0;i<=2;i++)
        for(j=0;j<=3;j++)
            if(a[i][j]>max)
            {
                max=a[i][j];
                row=i;
                colum=j;
            }
            cout<<"max="<<max<<",row="<<row<<",colum="<<colum<<endl;
            return 0;
}
 
/*
用指针类型的数据作函数参数比较大小
*/
#include<iostream>
using namespace std;
int main()
{
    void exchange(int *,int *,int *);
    int a,b,c,*p1,*p2,*p3;
    cin>>a>>b>>c;
    p1=&a;p2=&b;p3=&c;
    exchange(p1,p2,p3);
    cout<<a<<" "<<b<<" "<<c<<endl;
    return 0;
}
 
void exchange(int *q1,int *q2,int *q3)
    void swap(int *,int *);
{
    if(*q1>*q2) swap(q1,q2);
    if(*q1>*q3) swap(q1,q3);
    if(*q2>*q3) swap(q2,q3);
}
 
void swap(int *pt1,int *pt2)
{
    int temp;
    temp=*pt1;
    *pt1=*pt2;
    *pt2=temp;
}