一维数组输出杨辉三角

Question

#做了很久还是不会，能帮忙看一下是哪里错了嘛谢谢(；´д｀)ゞ

#include <iostream>
using namespace std;

int shuzu(int n) { //确定数组个数,同时用于计算当前位置
    int f;
    if (n == 1) {
        int f = 1;
    }
    if (n > 1) {
        f = n + shuzu(n - 1);
    }
    cout << f;
    return (f);
}

int derta(int n) { //输出
    int a[shuzu(n) + 1];
    cout << shuzu(n) + 1;
    a[1] = 1;
    a[2] = 1;
    a[3] = 1;
    if (n == 1) {
        cout << 1;
    } else if (n == 2) {
        cout << 1 << endl;
        cout << 1 << " " << 1;
    } else {
        cout << 1 << endl;
        cout << 1 << " " << 1;
        for (int i = 3; i <= n; i++) {
            for (int j = 1; j <= i; j++) {
                if (j == 1 || j == i) {
                    cout << 1 << " ";
                } else {
                    a[shuzu(i - 1) + j] = a[shuzu(i - 2) + j] + a[shuzu(i - 2) + j - 1];
                }
            }
            cout << endl;
        }
    }
}

int main() {
    int n;
    cout << "输入要输出的行数" << endl;
    cin >> n;
    derta(n);
}

Answer 1

修改的地方在代码里注释了，修改后运行结果：

4是输入，11是在你derta函数开始的地方的一个输出，从第三行开始是杨辉三角。

代码：

#include <iostream>
using namespace std;

int shuzu(int n) { //确定数组个数,同时用于计算当前位置
    int f;
    if (n == 1) {
        f = 1; //修改 int 去掉
    }
    if (n > 1) {
        f = n + shuzu(n - 1);
    }
    //cout << f;  //修改 删掉这一行
    return (f);
}

int derta(int n) { //输出
    int *a=new int[shuzu(n) + 1];
    cout << shuzu(n) + 1 << endl; //修改 加了个回车
    a[1] = 1;
    a[2] = 1;
    a[3] = 1;
    if (n == 1) {
        cout << 1;
    }
    else if (n == 2) {
        cout << 1 << endl;
        cout << 1 << " " << 1;
    }
    else {
        cout << 1 << endl;
        cout << 1 << " " << 1 << endl;//修改 添加了回车
        for (int i = 3; i <= n; i++) {
            for (int j = 1; j <= i; j++) {
                if (j == 1 || j == i) {
                    cout << 1 << " ";
                    a[shuzu(i - 1) + j] = 1; // 修改 添加这一行
                }
                else {
              
                    a[shuzu(i - 1) + j] = a[shuzu(i - 2) + j] + a[shuzu(i - 2) + j - 1];
                    cout << a[shuzu(i - 1) + j] << " "; //修改，添加这一行
                }
            }
            cout << endl;
        }
    }
    return 0;
}

int main() {
    int n;
    cout << "输入要输出的行数" << endl;
    cin >> n;
    derta(n);
}