One of the C language practical projects is greedy snake

friends , After me c Knowledge of the first ten chapters of language , Everyone should have started , I personally think that learning c The best way to use language is to make wheels , Writing projects is the best way to improve , We can connect the knowledge we have learned .

Today we write a practical project, snake ： Core will use Array and gotoxy（）; function

Let's look at the finished product first ：

This is a somewhat crude snake program , Although simple, finding and solving problems when writing is the most valuable asset .

Let's first look at what this program has ：

1. Map

2. The snake

3. food

According to these three, we will divide the greedy snake program into modules ：

1. Map module

2. Randomly generate food modules

3. Initialize snake module

4. Greedy snake mobile module

5. Game status module

6. Coordinate control module

Analysis complete , We began to get to the point ：

One Map module

The code is as follows

void createMap() {
	for (int i = 0 + MOVE_CENTER; i < MAP_WIDTH + MOVE_CENTER; i += 2) {// Up and down 
		gotoxy(i, 0);// change x,y unchanged -> Top edge 
		printf(MAP_MODE);

		gotoxy(i, MAP_HEIGHT - 1);// change x,y unchanged -> The bottom side 
		printf(MAP_MODE);
	}

	for (int i = 0; i < MAP_HEIGHT; i++) {// Left and right 
		gotoxy(0 + MOVE_CENTER, i);// change y,x unchanged -> The leftmost side 
		printf(MAP_MODE);

		gotoxy(MAP_WIDTH + MOVE_CENTER, i);// change y,x unchanged -> The rightmost side 
		printf(MAP_MODE);
	}
	// Change the cursor position , Make it not affect the beauty 
	gotoxy(96, 0);

	// Initialize snake 
	initSnake();
}

First, we know the first knowledge point by writing a map ：gotoxy（int x, int y）; function ：

gotoxy(int x, int y) yes #include<windows.h>  A function declared in , The function is to move the cursor to the specified position . In Contemporary Visual C++ or GCC You can customize this function in .

I drew a picture , So that you can understand ：

  The upper left corner is the origin （0,0）,x Increase to the right ,y Up and down .

How did you draw this box map ？：

First, we draw the upper and lower boxes ：

for (int i = 0 + MOVE_CENTER; i < MAP_WIDTH + MOVE_CENTER; i += 2) { // Up and down

         gotoxy(i, 0);// change x,y unchanged -> Top edge

         printf(MAP_MODE);

         gotoxy(i, MAP_HEIGHT - 1);// change x,y unchanged -> The bottom side

         printf(MAP_MODE);

    }

utilize for Cycle output our MAP_MODE Square box , Then assign a value to the coordinate function and print circularly

You may be a little confused , Why i+=2 instead of i++, because ■, This thing , Occupy two cursor widths ;

Here we define the macro ：

#defineMAP_MODE"■"// Map module

#defineMAP_WIDTH 80// Map length

#defineMAP_HEIGHT 30// Map width

#defineMOVE_CENTER 12// Move the map

Why use macros to define ？ For the convenience of our next revision , There is no need to take and modify the module separately , Modify the macro definition directly .

We set the length of the map as 80, Width is 30;

To move the position is to move the map to the right , Can be more beautiful

Be careful ：■, This thing , Occupy two cursor widths ;

well , Similarly, we began to draw the left and right sides ：

for (int i = 0; i < MAP_HEIGHT; i++) { // Left and right

         gotoxy(0 + MOVE_CENTER, i);// change y,x unchanged -> The leftmost side

         printf(MAP_MODE);

         gotoxy(MAP_WIDTH + MOVE_CENTER, i);// change y,x unchanged -> The rightmost side

         printf(MAP_MODE);

    }

Finally, we move the cursor outside the map , So as not to affect reading ：

// Change the cursor position , Make it not affect the beauty

    gotoxy(96, 0);

Then initialize the snake , Let's write first , I'll talk about initializing the snake module later ：

// Initialize snake

    initSnake();

}

Two Coordinate module

Because we used this in the map module gotoxy(); function , It belongs to the coordinate module , So let's talk about this module ：

void gotoxy(int x, int y) {// System auxiliary function 
	COORD pos = { x, y };
	HANDLE hOut = GetStdHandle(STD_OUTPUT_HANDLE);
	SetConsoleCursorPosition(hOut, pos);
}

gotoxy(), According to the coordinates assigned by you , Move the cursor to the corresponding place .

You just have to remember , Use gotoxy(); Function you have to define it like this , And bring the header #include<windows.h>// In order to use gotoxy( Cursor movement function )

The coordinate function to be used next time , Direct application ;

3、 ... and Randomly generate food modules

The code is as follows ：

void createFood() {
	// Random food 
	srand(time(NULL));// Random seeds 
	int isCreate = 1;// Indicates whether food can be created 
	food.x = rand() % (MAP_WIDTH - 4 + 2) + MOVE_CENTER;
	food.y = rand() % (MAP_HEIGHT - 1 + 1);

	if (food.x % 2 == 0) {// Satisfy x Coordinates are even 
		// The coordinates of food cannot be on the snake 
		for (int i = 0; i < snake.currentLen; i++) {
			if (snake.x[i] == food.x && snake.y[i] == food.y) {
				isCreate = 0;
			}

			if (isCreate) {
				gotoxy(food.x, food.y);
				printf(MAP_MODE);
				flag = 0;
				// Change the cursor position , Make it not affect the beauty 
				gotoxy(96, 0);
			}
		}
	}
}

Let's analyze the food first , Food is also a box , He has x And y coordinate .

Analysis complete , Let's create the structure ：

structFood { // Food structure

    int x;

    int y;

}food;

Okay , We have food , Now we're going to randomly generate it in our map , That is to say, his range of activities ：

How random ？

srand(time(NULL));// Random seeds

meanwhile time() The function should bring the header file #include<time.h>// Random seeds to appear food , Because it is the use of system time .

The purpose of this order is Use system time , Returns a random number .

meanwhile , We need to make food in the place we want ：

No more outside the map , It cannot be produced on the body of a snake .

Let's simply define a int isCreate = 1;// Indicates whether food can be created

The following code represents ： The food x Coordinates and y Where coordinates can be generated ：

food.x = rand() % (MAP_WIDTH - 4 + 2) + MOVE_CENTER;

 food.y = rand() % (MAP_HEIGHT - 1 + 1);

If you don't understand rand function , Please click the link below to understand , We won't go into details ：

https://blog.csdn.net/cmm0401/article/details/54599083

After understanding, you may want to ask , Why is food x The coordinates are at 4 To the width of the map , because ■, This thing , Occupy two cursor widths , Take a 2;

Write another for loop , Prevent food from forming on snakes ：

if (food.x % 2 == 0) { // Satisfy x Coordinates are even because ■, This thing , Occupy two cursor widths , Take a 2;

         // The coordinates of food cannot be on the snake

         for (int i = 0; i < snake.currentLen; i++) {

             if (snake.x[i] == food.x && snake.y[i] == food.y) {

                  isCreate = 0;

             }

snake Structure we will talk about later ,snake.currentLen Is the length of the snake ：

Then we write something that can produce food if loop ;

if (isCreate) {

                  gotoxy(food.x, food.y);

                  printf(MAP_MODE);

                  flag = 0;

                  // Change the cursor position , Make it not affect the beauty

                  gotoxy(96, 0);

             }

flag Is the global variable I defined ：int flag = 1;// Need to produce food

Four Initialize snake module

The code is as follows ：

void initSnake() {
	snake.currentLen = INITLEN;
	snake.x[0] = MAP_WIDTH / 2 + MOVE_CENTER;
	snake.y[0] = MAP_HEIGHT / 2;

	gotoxy(snake.x[0], snake.y[0]);
	printf(SNAKE_HEAD);

	// Print out the snake with a cycle , The snake's body is connected to the back of the snake's head 
	for (int i = 1; i < snake.currentLen; i++) {
		snake.x[i] = snake.x[i - 1] + 2;
		snake.y[i] = snake.y[i - 1];

		gotoxy(snake.x[i], snake.y[i]);
		printf(SNAKE_BODY);
	}

First, we write about the structure of snake. We need to know what it is made of ：

x coordinate ,y coordinate , And the length of the snake , Snakes are definitely not made up of a single coordinate , We use arrays to represent .

Based on this, we begin to define the snake structure ：

structSnake { // The structure of a snake

    int x[MAXLEN];

    int y[MAXLEN];

    int currentLen;// The length of the current snake x[0],y[0] -> Snakehead

}snake;

Define macro variables

#defineINITLEN 3// Define the initial length of the snake

#defineMAXLEN 30// Define the maximum length of the snake

#defineSNAKE_HEAD"⊙"// Snakehead

#defineSNAKE_BODY"●"// Snake-body.

without doubt , Snakehead is the first element of the array x[0]y[0];

snake.currentLen = INITLEN;  // The snake length is defined as the initial length

    snake.x[0] = MAP_WIDTH / 2 + MOVE_CENTER;        // Snakehead x The coordinates appear in the center of the map

    snake.y[0] = MAP_HEIGHT / 2;                                     //y The coordinates should also be in the center

    gotoxy(snake.x[0], snake.y[0]);                                    // Move the cursor to the center of the map

    printf(SNAKE_HEAD);                                                  // Output snakehead

When the snake head is finished, let's write the snake body ：

// Print out the snake with a cycle , The snake's body is connected to the back of the snake's head

    for (int i = 1; i < snake.currentLen; i++) {

         snake.x[i] = snake.x[i - 1] + 2;             // Add 2 Because the box occupies two spaces

         snake.y[i] = snake.y[i - 1];

         gotoxy(snake.x[i], snake.y[i]);

         printf(SNAKE_BODY);

    }

    // Change the cursor position , Make it not affect the beauty

    gotoxy(96, 0);

5、 ... and Snake mobile module

The code is as follows ：

void moveSnake() {

	if (_kbhit()) {// Monitor keyboard input 
		fflush(stdin);
		direct = _getch();
	}

	// Erase the last snaketail 
	gotoxy(snake.x[snake.currentLen - 1], snake.y[snake.currentLen - 1]);
	printf("  ");// Print two cursor size spaces 

	// Start replacing coordinates , Move the snake 
	for (int i = snake.currentLen - 1; i > 0; i--) {
		snake.x[i] = snake.x[i - 1];
		snake.y[i] = snake.y[i - 1];
		gotoxy(snake.x[i], snake.y[i]);
		printf(SNAKE_BODY);
	}

	switch (direct) {
	case 'w':
	case 'W':
		snake.y[0]--;
		break;

	case 's':
	case 'S':
		snake.y[0]++;
		break;

	case 'a':
	case 'A':
		snake.x[0] -= 2;
		break;

	case 'd':
	case 'D':
		snake.x[0] += 2;
		break;
	}

	// After moving , The position of the new snake head 
	gotoxy(snake.x[0], snake.y[0]);
	printf(SNAKE_HEAD);

	// Change the cursor position , Make it not affect the beauty 
	gotoxy(96, 0);

	// Determine whether the coordinates of the snake head are equal to the food 
	if (snake.x[0] == food.x && snake.y[0] == food.y) {
		snake.currentLen++;
		flag = 1;
	}

}

First , We encounter functions we are not familiar with kbhit（） function , Please see the following link to explain , We won't go into details ：

https://blog.csdn.net/liuhhaiffeng/article/details/54572521?spm=1001.2101.3001.6650.1&utm_medium=distribute.pc_relevant.none-task-blog-2%7Edefault%7ECTRLIST%7ERate-1.pc_relevant_aa&depth_1-utm_source=distribute.pc_relevant.none-task-blog-2%7Edefault%7ECTRLIST%7ERate-1.pc_relevant_aa&utm_relevant_index=2

After reading it, you will know that he monitors keyboard input , Because we need to use the keyboard to control the movement of the snake .

Don't forget to bring your header when you use it #include<conio.h>// Monitor keyboard input

Let's get to know , How greedy snakes move , Ate a food , Greedy snake grows one space ,, Snake moves. Are all the squares moving , Not snake head and set to move , The snake tail movement is to erase the last space , Do you remember the old version of the pixel game "brave vs. dragon" we played when we were children , It is also made by using this frame by frame change , Then visually, you think the brave are moving .

Return to the right topic ：

How to erase our snake tail ：

// Erase the last snaketail

    gotoxy(snake.x[snake.currentLen - 1], snake.y[snake.currentLen - 1]);

    printf("  ");// Print two cursor size spaces

Snake's x Change the coordinates to length -1,y Coordinates also -1. Then turn the box into “  ”, overwrite .

Then we began to move the snake ：

/ Start replacing coordinates , Move the snake

    for (int i = snake.currentLen - 1; i > 0; i--) {

         snake.x[i] = snake.x[i - 1];

         snake.y[i] = snake.y[i - 1];

         gotoxy(snake.x[i], snake.y[i]);

         printf(SNAKE_BODY);

    }

Write a for The cycle keeps checking x-1 The coordinates of are assigned to x, The former coordinate is given to the latter , Isn't this just exercise , Then at the coordinates , We export snake bodies .

The head of a snake controls its body , How to control the snake head , This is what we talked about before kbhit() Function , Since the keyboard input is monitored , Then let's input the key to control the coordinates of the snake head .

Macro definition ：int direct = 'a';// The default key is a

Why do I need this macro definition , Because it defaults that our snake moves to the left .

switch (direct) {

    case'w':

    case'W':

         snake.y[0]--;           // Up

         break;

    case's':

    case'S':

         snake.y[0]++;              // Down

         break;

    case'a':

    case'A':

         snake.x[0] -= 2;            // towards the left

         break;

    case'd':

    case'D':

         snake.x[0] += 2;             // towards the right

         break;

    }

    // After moving , The position of the new snake head

    gotoxy(snake.x[0], snake.y[0]);

    printf(SNAKE_HEAD);

    // Change the cursor position , Make it not affect the beauty

    gotoxy(96, 0);

use switch Statement control keys to manipulate snake head coordinates , So we can control the snake to move .

Then the snake eats food to increase its length ：

// Determine whether the coordinates of the snake head are equal to the food

    if (snake.x[0] == food.x && snake.y[0] == food.y) {

         snake.currentLen++;

         flag = 1;

    }

Well understood. , Be a snake head xy Coordinates and food xy The coordinates coincide , The length of the snake is increased by one .

flag Is our macro definition , We use it to control food production , Because food can't be produced there without you eating it , Eat one and make one .

6、 ... and Game status module

The code is as follows ：

int statement() {// Judge the current state of the game 
	// Judge whether the snake head hit the wall 
	if (snake.x[0] == 0 + MOVE_CENTER || snake.x[0] == MAP_WIDTH + MOVE_CENTER || snake.y[0] == 0 || snake.y[0] == MAP_HEIGHT - 1) {
		return 1;
	}
	// Snake head eats any part of his body 

	for (int i = 1; i < snake.currentLen; i++) {
		if (snake.x[0] == snake.x[i] && snake.y[0] == snake.y[i]) {
			return 1;
		}
	}
	return 0;
}

Greedy snakes can't go on forever , How does the game end ？

Two cases ：

One is that the snake hit the wall , Two snakes bit their bodies

First look at the first one ：

// Judge whether the snake head hit the wall

    if (snake.x[0] == 0 + MOVE_CENTER || snake.x[0] == MAP_WIDTH + MOVE_CENTER || snake.y[0] == 0 || snake.y[0] == MAP_HEIGHT - 1) {

         return 1;

    }

How to judge whether the snake hit the wall ？ use if Sentence when the snake x Coordinates and y When the coordinates coincide with the coordinates of the map border , End the game .

Look at the second one ：

for (int i = 1; i < snake.currentLen; i++) {

         if (snake.x[0] == snake.x[i] && snake.y[0] == snake.y[i]) {

             return 1;

         }

    }

    return 0;

It's simple, isn't it , Write a for loop , Then snake head xy Coordinates and snake body xy Exit the game when the coordinates are equal

.

main function

Six modules are completed , Let's write main function ：

int main() {

    createMap();

    while (1) {

         Sleep(300);         // Let the food not appear so fast

         if (flag) {

             createFood();

         }

         moveSnake();

         if (statement()) {

             gotoxy(MAP_WIDTH / 2, MAP_HEIGHT / 2);// Enter game over

             printf("Game Over!\n");

             // Change the cursor position , Make it not affect the beauty

             gotoxy(96, 0);

             exit(0);

         }

    }

Conclusion

This greedy snake is simple , But as our beginner's project, it has a certain degree of difficulty , I followed this procedure b A video of the station was knocked out bit by bit , Why write this article , Because I think we should write our own understanding when making wheels , You can't build wheels all day , What is the wheel? I don't know when I ask you , Only by writing your own understanding can you turn knowledge into your own things .

So I wrote down my understanding and development process , I hope it can help readers understand , The author is a senior student who is looking for internship , Limited ability , If you have any suggestions, please don't hesitate to comment .