how to get coordinates of a polygon in input using arrays

Question

Vertices of polygon?4

vertex 1? 0 0

vertex 2? 0 1

vertex 3? 1 0

vertex 4? 1 1

Answer 1

I have given in both C and Python with three three code each

C

#include <stdio.h>

#include <stdlib.h>

void main(){

    int i,n,*x,*y,*z;

    printf("Enter the no. of edges or no. of vertices of the polygon : ");

    scanf("%d",&n);

    x=(int*)malloc(n*sizeof(int));

    y=(int*)malloc(n*sizeof(int));

    z=(int*)malloc(n*sizeof(int));

    for(i=0;i<n;i++){

        printf("Enter x cordinate of vertex %d :",i+1);

        scanf("%d",&x[i]);

        printf("Enter y cordinate of vertex %d :",i+1);

        scanf("%d",&y[i]);

        printf("Enter z cordinate of vertex %d :",i+1);

        scanf("%d",&z[i]);

    }

    printf("Following are the vertex of the polygon :\n");

    for(i=0;i<n;i++){

        printf("v%d(%d,%d,%d)\n",i+1,x[i],y[i],z[i]);

    }

}

PYTHON

d={}
n=int(input("Enter the number of edges or vertices: "))
for i in range(n):
    a=int(input("Enter the x-coordinate of vertex"+str(i+1)+" : "))
    b=int(input("Enter the y-coordinate of vertex"+str(i+1)+" : "))
    c=int(input("Enter the z-coordinate of vertex"+str(i+1)+" : "))
    d[i]=[a,b,c]
print("Following are the coordinates of each vertex of the polygon:")
for i in range(n):
    print("V",i+1,"(",d[i][0],",",d[i][1],",",d[i][2],")")

Comments

In C, you did not free your allocated memory.
Also, the poster seemed to have worked in the 2D space, but you provided an answer in 3D space.

Answer 2

#include <iostream>  // 引入 iostream 標頭檔，提供輸入/輸出功能
#include <vector>    // 引入 vector 標頭檔，提供動態陣列功能
#include <iomanip>   // 引入 iomanip 標頭檔，提供格式化輸出功能
using namespace std; // 使用 std 命名空間

int main()
{
    int n;  // n 用來儲存多邊形的頂點數量

    // ================================================================
    // 第 1 步：詢問使用者多邊形有多少個頂點
    // ================================================================
    cout << "請輸入多邊形的頂點數量：";
    cin >> n;

    // 檢查頂點數量是否有效
    if (n <= 0)
    {
        cout << "錯誤：頂點數量必須大於 0！" << endl;
        return 1;
    }

    // ================================================================
    // 第 2 步：宣告三個 vector（動態陣列），分別儲存 x、y、z 座標
    // ================================================================
    // 每個頂點需要 x、y、z 三個座標，因此用三個 vector 分別儲存
    // 使用 vector<double> 可以動態分配記憶體，不需要預先知道大小
    vector<double> x(n);  // x 座標陣列，大小為 n
    vector<double> y(n);  // y 座標陣列，大小為 n
    vector<double> z(n);  // z 座標陣列，大小為 n
    // 註：使用 double 而非 int，讓座標可以接受小數

    // ================================================================
    // 第 3 步：輸入每個頂點的座標
    // ================================================================
    for (int i = 0; i < n; i++)
    {
        cout << "\n頂點 " << (i + 1) << " 的座標：";
        cout << "\n  輸入 x 座標：";
        cin >> x[i];  // 將第 i 個頂點的 x 座標存入陣列

        cout << "  輸入 y 座標：";
        cin >> y[i];  // 將第 i 個頂點的 y 座標存入陣列

        cout << "  輸入 z 座標：";
        cin >> z[i];  // 將第 i 個頂點的 z 座標存入陣列
    }

    // ================================================================
    // 第 4 步：顯示所有頂點的座標資訊
    // ================================================================
    cout << "\n========================================" << endl;
    cout << "以下是多邊形的所有頂點座標：" << endl;
    cout << "========================================" << endl;

    for (int i = 0; i < n; i++)
    {
        // 使用 setw 和 setprecision 讓輸出更整齊
        cout << "頂點 " << setw(2) << (i + 1) << ": ("
             << setprecision(2) << fixed << x[i] << ", "
             << y[i] << ", "
             << z[i] << ")" << endl;
    }

    cout << "========================================" << endl;

    return 0;  // 程式正常結束
}

Comments

You check if n <= 0, but what about n = 1 or n = 2? Those are not valid polygons.