Add Snake game in C under games/

games/csnake.c

@@ -0,0 +1,230 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <conio.h>   // for _kbhit() and _getch() -> keyboard input
+#include <time.h>    // for random food generation (using time as seed)
+#include <windows.h> // for system("cls") on Windows
+
+// ==== Game Constants ====
+#define ROWS 25      // Number of rows in the game board
+#define COLS 25      // Number of columns in the game board
+#define MAX_LEN 256  // Maximum snake length
+
+// ==== Global Variables ====
+
+// Board matrix (ROWS x COLS)
+char board[ROWS][COLS];
+
+// Game states
+int isgameover = 0;  // Flag to end the game
+int eaten = 1;       // Indicates if food has been eaten
+int snake_len = 1;   // Initial snake length
+int dx = 1, dy = 0;  // Initial direction (moving right)
+
+// Snake head position (start from middle of board)
+int posx = ROWS / 2;
+int posy = COLS / 2;
+
+// Snake body coordinates (a[i][0] -> row, a[i][1] -> col)
+int a[MAX_LEN][2];
+
+// Food position
+int foodx, foody;
+
+// Timing variables
+clock_t last = 0;    // To track last move time
+int delay = 150;     // Snake speed (milliseconds)
+
+// ==== FUNCTIONS ====
+
+// Draw empty board (borders = '*', inside = ' ')
+void draw_board() {
+    for (int i = 0; i < ROWS; i++) {
+        for (int j = 0; j < COLS; j++) {
+            if (i == 0 || j == 0 || i == ROWS - 1 || j == COLS - 1) {
+                board[i][j] = '*';  // Border
+            } else {
+                board[i][j] = ' ';  // Empty space
+            }
+        }
+    }
+}
+
+// Place snake on board
+void snake() {
+    // Shift body (move each segment to the previous segment’s position)
+    for (int i = snake_len; i > 0; i--) {
+        a[i][0] = a[i - 1][0];
+        a[i][1] = a[i - 1][1];
+    }
+
+    // Update head position
+    a[0][0] = posx;
+    a[0][1] = posy;
+
+    // Draw snake on board
+    for (int k = 0; k < snake_len; k++) {
+        if (k == 0)
+            board[a[k][0]][a[k][1]] = '@'; // Snake head
+        else
+            board[a[k][0]][a[k][1]] = 'O'; // Snake body
+    }
+}
+
+// Print board to screen (with ANSI colors)
+void print_board() {
+    fflush(stdout);
+    printf("\033[H"); // Move cursor to top-left (instead of clearing screen)
+
+    for (int i = 0; i < ROWS; i++) {
+        for (int j = 0; j < COLS; j++) {
+            if (i == 0 || j == 0 || i == ROWS - 1 || j == COLS - 1)
+                printf("\033[35m%c\033[0m", board[i][j]);   // Purple border
+            else if (i == foodx && j == foody)
+                printf("\033[31m%c\033[0m", board[i][j]);   // Red food
+            else
+                printf("\033[32m%c\033[0m", board[i][j]);   // Green snake / empty
+        }
+        printf("\n");
+    }
+}
+
+// Update snake’s head position
+void transform(int x, int y) {
+    posx += x;
+    posy += y;
+}
+
+// Handle keyboard input
+void input() {
+    if (_kbhit()) {  // Check if a key was pressed
+        int m = _getch();
+
+        // Handle arrow keys (they come as two-byte sequence)
+        if (m == 0 || m == 224) {
+            int arrow = _getch(); // Get actual arrow code
+            switch (arrow) {
+            case 72: // Up
+                if (dx != 1 || snake_len == 1) { dx = -1; dy = 0; }
+                break;
+            case 80: // Down
+                if (dx != -1 || snake_len == 1) { dx = 1; dy = 0; }
+                break;
+            case 75: // Left
+                if (dy != 1 || snake_len == 1) { dx = 0; dy = -1; }
+                break;
+            case 77: // Right
+                if (dy != -1 || snake_len == 1) { dx = 0; dy = 1; }
+                break;
+            }
+        } else {
+            // WASD keys as alternative controls
+            switch (m) {
+            case 'w': if (dx != 1 || snake_len == 1) { dx = -1; dy = 0; } break;
+            case 's': if (dx != -1 || snake_len == 1) { dx = 1; dy = 0; } break;
+            case 'a': if (dy != 1 || snake_len == 1) { dx = 0; dy = -1; } break;
+            case 'd': if (dy != -1 || snake_len == 1) { dx = 0; dy = 1; } break;
+            case 'q': isgameover = 1; break; // Quit game
+            }
+        }
+    }
+}
+
+// Check collisions (walls or self)
+void collision() {
+    // Check wall collision
+    if (posx == ROWS - 1 || posx == 0 || posy == 0 || posy == COLS - 1) {
+        isgameover = 1;
+    }
+
+    // Check self collision
+    for (int i = 1; i < snake_len; i++) {
+        if (posx == a[i][0] && posy == a[i][1]) {
+            isgameover = 1;
+        }
+    }
+}
+
+// Generate food if needed
+void food() {
+    if (eaten) {
+        int max = ROWS - 2, min = 1;
+        foodx = (rand() % (max - min + 1)) + min;
+        foody = (rand() % (max - min + 1)) + min;
+        eaten = 0; // Reset eaten flag
+    }
+    board[foodx][foody] = '#'; // Place food on board
+}
+
+// Check if food is eaten
+void Eaten() {
+    if (posx == foodx && posy == foody) {
+        eaten = 1;
+        snake_len++; // Increase length
+        if (snake_len >= MAX_LEN) {
+            printf("You won!\n");
+            exit(0);
+        }
+    }
+}
+
+// ==== MAIN FUNCTION ====
+int main() {
+    int difficulty = 0;
+    srand(time(NULL)); // Seed random number generator
+
+    // Show game instructions
+    printf("========== Snake Game ==========\n");
+    printf("Controls:\n");
+    printf("  Arrow Keys or WASD to move\n");
+    printf("  Press 'q' to quit\n\n");
+
+    // Difficulty selection
+    printf("Choose Difficulty (1 = Easy, 2 = Medium, 3 = Hard): ");
+    if (scanf("%d", &difficulty) != 1) {
+        printf("Invalid input! Defaulting to Medium.\n");
+        difficulty = 2;
+    }
+
+    switch (difficulty) {
+    case 1: delay = 125; break; // Easy
+    case 2: delay = 100; break; // Medium
+    case 3: delay = 50; break;  // Hard
+    default:
+        printf("Invalid choice! Defaulting to Medium.\n");
+        delay = 100;
+        break;
+    }
+    system("cls"); // Clear screen
+
+    // Hide cursor for smooth rendering
+    printf("\033[?25l");
+
+    last = clock(); // Start timer
+
+    // Move cursor to top-left
+    printf("\033[H");
+
+    // ==== Game Loop ====
+    while (!isgameover) {
+        input(); // Handle input
+
+        clock_t now = clock();
+        // Move snake after a delay (speed control)
+        if ((now - last) * 1000 / CLOCKS_PER_SEC >= delay) {
+            transform(dx, dy); // Move snake
+            Eaten();           // Check if food eaten
+            collision();       // Check collisions
+            last = now;        // Reset timer
+
+            draw_board();      // Redraw board
+            snake();           // Draw snake
+            food();            // Place food
+            print_board();     // Display board
+        }
+    }
+
+    // Restore cursor
+    printf("\033[?25h");
+    printf("Game Over!\n");
+    return 0;
+}

project_euler/problem_6/o(1)sol.c

@@ -0,0 +1,38 @@
+// Project Euler Problem 6
+// Find the difference between the sum of the squares of the first n natural
+// numbers and the square of the sum of the first n natural numbers.
+//
+// Formula used:
+// Sum of squares = n(n+1)(2n+1)/6
+// Square of sum  = (n(n+1)/2)^2
+//
+// Example:
+// Input : 100
+// Output: 25164150
+
+#include <stdio.h>
+
+// Function to compute sum of squares using formula
+long long sum_of_square(int n)
+{
+    return (long long)n * (n + 1) * (2 * n + 1) / 6;
+}
+
+// Function to compute square of sum using formula
+long long square_of_sum(int n)
+{
+    long long sum = (long long)n * (n + 1) / 2;
+    return sum * sum;
+}
+
+int main()
+{
+    int n;
+    scanf("%d", &n);
+
+    long long answer = square_of_sum(n) - sum_of_square(n);
+    printf("%lld\n", answer);
+
+    return 0;
+}
+//this calculates in o(1) ,enter the n till which u want to find. for our case (in question) its 100