C++实现前20位五角数，每行输出5个

![img](https://img-mid.csdnimg.cn/release/static/image/mid/ask/992296860736119.jpg "#lef

#include <stdio.h>
int getPentagonaNumber(int n)
{
    return n*(3*n-1)/2;
}
int main()
{
    int i = 0,j=1;
    while(i<20)
    {
        printf("%d ",getPentagonaNumber(j));
        j++;i++;
        if(i%5==0)
            printf("\n");
    }
    return 0;
}

#include<iostream>

int getPentagonaNumber (int n) {
    return n * ( 3 * n - 1) / 2;
}
int main () {
    for (int i =0; i < 4; i++) {
        for (int j =0; j < 5; j++) {
            cout << getPentagonaNumber(i * 5 + j + 1);
        }
        cout << endl;
   }
}