【求助】c++回文素数怎么做？ - 编程论坛

#2

ZJYTY2019-01-25 10:14

程序代码：

#include<iostream>
#include<vector>
#include<time.h>

using namespace std;

class PrimePalindrome
{
public:
    void PrimeNumbers();
    void PalindromeNumbers();
    void showNumbers();
    void inputNum();
private:
    int beginNum;
    int endNum;
    vector<int> palindrome;
    vector<int> palindromePrime;
};

void PrimePalindrome::PalindromeNumbers()
{
    int s, y = 0;
    for (int i = beginNum; i <= endNum;i++)
    {
        if (i>2 && i%2 == 0)
            continue;
        s = i;
        while (s > 0)
        {
            y = y * 10 + s % 10;
            s = s / 10;
        }
        if (y==i)
        {
            palindrome.push_back(i);
        }
        y = 0;
    }
}

void PrimePalindrome::PrimeNumbers()
{
    int a = 0;
    int i;
    auto itr = palindrome.begin();
    for (itr; itr != palindrome.end(); ++itr)
    {
        for (i = 2; i <= (*itr);++i)
        {
            if ((*itr) % i == 0)
                break;
        }
        if (i == (*itr)){
            palindromePrime.push_back(*itr);
        }
    }
}

void PrimePalindrome::showNumbers()
{
    cout << "回文素数列表：" << endl;
    for (auto itr = palindromePrime.begin(); itr != palindromePrime.end();++itr)
    {
        cout << *itr << endl;
    }
}
void PrimePalindrome::inputNum()
{
    cout << "Input the beginNum : ";
    cin >> beginNum;
    while (!getchar());
    cout << "Input the endNum : ";
    cin >> endNum;
    while (!getchar());
}

int main()
{
    clock_t start, finish;
    double totaltime;

    PrimePalindrome pp;
    pp.inputNum();
    start = clock();
    pp.PalindromeNumbers();
    pp.PrimeNumbers();
    pp.showNumbers();

    finish = clock();
    totaltime = (double)(finish - start) / CLOCKS_PER_SEC;
    cout << "\n此程序的运行时间为" << totaltime << "秒！" << endl;
    getchar();
}

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测试范围2-100000，内存占用804K（任务管理器显示）

#3

asdfaad2019-01-25 12:12

回复 2楼 ZJYTY

auto itr = palindrome.begin();
这句报错了

#4

ZJYTY2019-01-25 13:30

回复 3楼 asdfaad

报什么错误？

若不支持auto,自己定义迭代器试一试：vector<int>::iterator itr

#5

asdfaad2019-01-25 13:40

回复 4楼 ZJYTY

我用的dev-c++
是把报错的那段换成你写的是吗

#6

ZJYTY2019-01-25 13:53

回复 5楼 asdfaad

这两个地方用到了auto

程序代码：

void PrimePalindrome::PrimeNumbers()
{
    int a = 0;
    int i;
    vector<int>::iterator itr = palindrome.begin();
    for (itr; itr != palindrome.end(); ++itr)
    {
        for (i = 2; i <= (*itr);++i)
        {
            if ((*itr) % i == 0)
                break;
        }
        if (i == (*itr)){
            palindromePrime.push_back(*itr);
        }
    }
}

void PrimePalindrome::showNumbers()
{
    cout << "回文素数列表：" << endl;
    for (vector<int>::iterator itr = palindromePrime.begin(); itr != palindromePrime.end();++itr)
    {
        cout << *itr << endl;
    }
}