C++题目记录

1.输出10000以内7的倍数或含数字7的数。

#include <iostream>

using namespace std;

int main() {
    for (int i = 1; i <= 10000; i++) {
        if (i % 7 == 0 || i % 10 == 7 || (i / 10) % 10 == 7 || (i / 100) % 10 == 7 || (i / 1000) % 10 == 7) {
            cout << i << endl;
        }
    }

    return 0;
}

2.将一个数分解成质数相乘的形式

#include <iostream>
using namespace std;
void primeFactorization(int number) {
  cout << number << ":";
  for (int i = 2; i <= number; ++i) {
    while (number % i == 0) {
      cout << " " << i;
      number /= i;
    }
  }
  cout << endl;
}
int main() {
  int number;
  cin >> number;
  primeFactorization(number);
  return 0;
}

3.输出n内的质数

#include <bits/stdc++.h>

using namespace std;

int main() {
bool sum;
    for (int i = 2; i <= 1000; i++) {sum=false;
        for(int x=2;x<(int)sqrt(i);x++)
        {

            if(i%x==0){sum=true;}
        }
        if(!sum){cout<<i<<" ";}
    }


    return 0;
}

4.

 

#include <bits/stdc++.h>
using namespace std;
int main(){
    long long n,via,jia,sum=0,sum1=0;
    cin>>n;
    for(long long i=2;i<n;i++)
    {
        if(n%i==0){
            for(long long x=2;x<=(int)sqrt(i);x++)
            {
                if(i%x==0){sum++;}
            }if(sum==0){
                via=n/i;
                for(long long x=2;x<=(int)sqrt(via);x++)
            {
                if(via%x==0){sum1++;}
            }if(sum1==0){
                    if(i<=via)cout<<i<<" "<<via<<endl;}
            }
        }
    }
}