能否写出以上问题的代码

当然可以，以下是一个简单的实现，仅供参考：

#include <iostream>
#include <cstdlib>
#include <vector>
#include <algorithm>
#include <cmath>
#include <SDL2/SDL.h>

const int SCREEN_WIDTH = 800;
const int SCREEN_HEIGHT = 600;
const int MAX_CYLINDER = 1500;
const int REQUEST_COUNT = 400;
const int REQUEST_RANGE[3] = {499, 999, 1499};
const int REQUEST_PERCENTAGE[3] = {50, 25, 25};
const int REQUEST_INTERVAL = 10;

SDL_Window* gWindow = NULL;
SDL_Renderer* gRenderer = NULL;

void initSDL() {
    SDL_Init(SDL_INIT_VIDEO);
    gWindow = SDL_CreateWindow("Elevator Scheduling Simulation", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN);
    gRenderer = SDL_CreateRenderer(gWindow, -1, SDL_RENDERER_ACCELERATED);
    SDL_SetRenderDrawColor(gRenderer, 0xFF, 0xFF, 0xFF, 0xFF);
    SDL_RenderClear(gRenderer);
}

void quitSDL() {
    SDL_DestroyRenderer(gRenderer);
    SDL_DestroyWindow(gWindow);
    gRenderer = NULL;
    gWindow = NULL;
    SDL_Quit();
}

int generateCylinder() {
    return rand() % MAX_CYLINDER;
}

void generateRequests(std::vector<int>& requests) {
    requests.reserve(REQUEST_COUNT);
    int rangeIndex = 0;
    for (int i=0; i<REQUEST_COUNT; ++i) {
        int range = REQUEST_RANGE[rangeIndex];
        requests.push_back(generateCylinder() % (range+1));
        int percentage = rand() % 100;
        if (percentage < REQUEST_PERCENTAGE[0]) {
            rangeIndex = 0;
        } else if (percentage < REQUEST_PERCENTAGE[0] + REQUEST_PERCENTAGE[1]) {
            rangeIndex = 1;
        } else {
            rangeIndex = 2;
        }
    }
}

int calculateDistance(int a, int b) {
    return std::abs(a - b);
}

int look(std::vector<int> requests, int start) {
    int distance = 0;
    int direction = 1;
    std::sort(requests.begin(), requests.end());
    auto it = std::lower_bound(requests.begin(), requests.end(), start);
    while (it != requests.end() || it != requests.begin()) {
        if (it == requests.end()) {
            direction = -1;
            it--;
        } else if (it == requests.begin()) {
            direction = 1;
        }
        int next = *it;
        distance += calculateDistance(start, next);
        start = next;
        it += direction;
    }
    return distance;
}

int cscan(std::vector<int> requests, int start) {
    int distance = 0;
    std::sort(requests.begin(), requests.end());
    auto it = std::upper_bound(requests.begin(), requests.end(), start);
    if (it == requests.end()) {
        it = requests.begin();
        distance += calculateDistance(start, *it);
        distance += calculateDistance(*it, MAX_CYLINDER - 1);
        distance += MAX_CYLINDER - 1;
        start = 0;
    }
    while (it != requests.end()) {
        int next = *it;
        distance += calculateDistance(start, next);
        start = next;
        it++;
    }
    distance += calculateDistance(start, MAX_CYLINDER - 1);
    distance += MAX_CYLINDER - 1;
    it = requests.begin();
    distance += calculateDistance(start, *it);
    start = *it;
    while (it != std::upper_bound(requests.begin(), requests.end(), start)) {
        int next = *it;
        distance += calculateDistance(start, next);
        start = next;
        it++;
    }
    return distance;
}

void drawAxis() {
    SDL_RenderDrawLine(gRenderer, 50, 50, 50, SCREEN_HEIGHT - 50);
    SDL_RenderDrawLine(gRenderer, 50, SCREEN_HEIGHT - 50, SCREEN_WIDTH - 50, SCREEN_HEIGHT - 50);
    for (int i=0; i<=MAX_CYLINDER; i+=100) {
        int y = SCREEN_HEIGHT - 50 - (int)std::round((double)i / MAX_CYLINDER * (SCREEN_HEIGHT - 100));
        SDL_RenderDrawLine(gRenderer, 45, y, 55, y);
    }
}

void drawRequest(int x, int y, int size) {
    SDL_Rect rect = {x - size / 2, y - size / 2, size, size};
    SDL_RenderFillRect(gRenderer, &rect);
}

void drawLine(int x1, int y1, int x2, int y2) {
    SDL_RenderDrawLine(gRenderer, x1, y1, x2, y2);
}

void simulate(std::vector<int> requests, int start, int (*schedule)(std::vector<int>, int)) {
    int current = start;
    int time = 0;
    for (const auto& request : requests) {
        SDL_SetRenderDrawColor(gRenderer, 0x00, 0x00, 0x00, 0xFF);
        int x1 = 50 + time * REQUEST_INTERVAL;
        int y1 = SCREEN_HEIGHT - 50 - (int)std::round((double)current / MAX_CYLINDER * (SCREEN_HEIGHT - 100));
        drawRequest(x1, y1, 10);
        SDL_SetRenderDrawColor(gRenderer, 0xFF, 0x00, 0x00, 0xFF);
        int x2 = 50 + (time+1) * REQUEST_INTERVAL;
        int y2 = SCREEN_HEIGHT - 50 - (int)std::round((double)request / MAX_CYLINDER * (SCREEN_HEIGHT - 100));
        drawRequest(x2, y2, 10);
        drawLine(x1, y1, x2, y2);
        current = request;
        time++;
        SDL_RenderPresent(gRenderer);
        SDL_Delay(100);
    }
    int distance = schedule(requests, start);
    std::cout << "Total distance: " << distance << std::endl;
    SDL_Delay(5000);
}

int main(int argc, char* argv[]) {
    initSDL();
    std::vector<int> requests;
    generateRequests(requests);
    drawAxis();
    simulate(requests, generateCylinder(), look);
    SDL_RenderClear(gRenderer);
    drawAxis();
    simulate(requests, generateCylinder(), cscan);
    quitSDL();
    return 0;
}

该代码实现了所述的基本思路，其中 `initSDL()` 和 `quitSDL()` 函数用于初始化和退出SDL库，`generateCylinder()` 函数用于生成随机的磁道号，`generateRequests()` 函数用于生成随机的请求序列，`calculateDistance()` 函数用于计算两个磁道号之间的距离，`look()` 函数和 `cscan()` 函数分别实现了LOOK算法和C-SCAN算法，`drawAxis()` 函数用于绘制坐标轴，`drawRequest()` 函数用于绘制请求点，`drawLine()` 函数用于绘制连线，`simulate()` 函数用于模拟算法的执行过程，并在图形界面上显示出来。