一半拋物線程式碼

#include <iostream>
using namespace std;

const int X=100, Y=100;

int main(){
    char screen[X][Y];
    
    // 初始化畫布
    for (int j=0; j<Y; j++)
        for(int i=0; i<X; i++)
            screen[i][j] = '_';
    
    // 繪製 y = x^2 的曲線
    for (int x=1; x<=30; x++)
        screen[3*x][(x*x)/10] = '*';
    
    // 輸出畫布
    for (int j=Y-1; j>=0; j--){
        for (int i=0; i<X; i++)
            cout << screen[i][j];
        cout << endl;
    }

    return 0;
}

輸出結果

完整拋物線程式碼

#include <iostream>
using namespace std;

const int X = 100, Y = 100;

int main(){
    char screen[X][Y];
    
    // 初始化畫布
    for (int j = 0; j < Y; j++)
        for(int i = 0; i < X; i++)
            screen[i][j] = '_';
    
    // 繪製 y = x^2 的曲線
    for (int x = -15; x <= 15; x++){
        int y = x * x;
        screen[3 * (x + 15)][y / 3] = '*';
    }
    
    // 輸出畫布
    for (int j = Y-1; j >= 0; j--){
        for (int i = 0; i < X; i++)
            cout << screen[i][j];
        cout << endl;
    }

    return 0;
}

輸出結果