在指针数组中查找主数

Question

这段代码运行良好，它告诉你输入一个数字，然后输入 for 循环中的数字，它检查它是否可以被 i 整除，如果为真，则打印非素数，如果不打印素数。

#include <iostream>
using namespace std;

int main() {
  int x;
  cin >> x;

  bool f = true;
  for (int i = 2; i < x; i++) {
    f = false;
    if (i % x == 0)
      f = true;
    if (f)
      cout << "not primary";
    else
      cout << "primary";
  }
}

但是当我将它转换为这样的数组时：

#include <iostream>
using namespace std;

int main() {
  cout << "the number of array:" << endl;
  int n;
  cin >> n;

  cout << "enter them = \n";
  int *p = new int[n];
  for (int i = 0; i < n; i++)
    cin >> p[i];

  bool f = true;
  for (int i = 0; i < n; i++)
    for (int j = 2; j < p[i]; j++) {
      f = false;
      if (p[i] % j == 0)
        f = true;
      if (f)
        cout << "This is not a primary number!\n";
      else
        cout << "this is a primary number!\n";
    }

  delete p;
}

它只存储第一个数字，我明白了，但是如何增加它 假设 n =3 所以 p[3] = {4,6,7}; 我的问题是如何在 j 条件下告诉编译器 if (p[0] % j) then(p[1] %j) 似乎只需要 p[0]

Answer 1

这样会好很多

#include <iostream>
using namespace std;

int main() {
  cout << "the number of array:" << endl;
  int n;
  cin >> n;

  cout << "enter them = \n";
  int *p = new int[n];
  for (int i = 0; i < n; i++)
    cin >> p[i];

  for (int i = 0; i < n; i++) {
    bool f = false; // we set f to false for each number
    for (int j = 2; j < p[i]; j++) {
      if (p[i] % j == 0) {
        f = true;
        break; // we break the loop if it's a prime number
      }
    }
    if (f)
      cout << p[i] << " is not a primary number!\n";
    else
      cout << p[i] << " is a primary number!\n";
  }

  delete[] p; // Here you forget brackets [], when you use new[] you must use delete[].
}

Doc 用于删除运算符。

我让一些问题像int。您不应该使用带符号的数字进行迭代或存储尺寸。因为你是初学者，我不想混淆你。所以我让它。