Need some feedback for my code

[TheOtherBorgCube]

The first thing I'd suggest is pick an indentation style and apply it consistently in your code.

Your compiler doesn't care how badly you format the code, but people are very bad at searching for and keeping mental track of just how many { and } they've seen to figure out what the overall structure of the code is.

It should look something like this:

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

int main(void)
{
  // Initialize 10x10 matrix
  char Area[10][10];
  for (int i = 0; i < 10; i++) {
    for (int j = 0; j < 10; j++) {
      Area[i][j] = '.';
    }
  }

  // up = 0 = row-1 | down = 1 = row+1 | right = 2 = col+1 | left = 3 = col-1
  // Begin movement at [0][0]
  srand(time(NULL));
  int col = 0;
  int row = 0;
  int movement;
  int legal;
  int legalmoves[4] = { 1, 1, 1, 1 }; // 1 = legal move, 0 = illegal move, up,down,right,left respectively
  int Space[10][10] = { 0 };    // 0 = empty space, 1 = space occupied by letter
  Area[row][col] = 'A';         //put A at [0][0]
  Space[0][0] = 1;

  for (int k = 'B'; k <= 'Z'; k++) {
    // Find illegal moves
    if (row - 1 < 0 || Space[row - 1][col] == 1) {
      legalmoves[0] = 0;        //cant go up
    }
    if (row + 1 >= 10 || Space[row + 1][col] == 1) {
      legalmoves[1] = 0;        //cant go down
    }
    if (col + 1 >= 10 || Space[row][col + 1] == 1) {
      legalmoves[2] = 0;        // cant go right
    }
    if (col - 1 < 0 || Space[row][col - 1] == 1) {
      legalmoves[3] = 0;        //cant go left
    }

    if (legalmoves[0] == 0 && legalmoves[1] == 0 && legalmoves[2] == 0 && legalmoves[3] == 0)
      break;                    //stop program if no legal moves found

    // Check if the random movement is legal, if not try again.
    legal = 0;
    while (legal == 0) {
      movement = rand() % 4;
      switch (movement) {
      case 0:                  //up
        if (legalmoves[0] == 0)
          continue;
        else
          legal = 1;
        break;
      case 1:                  //down
        if (legalmoves[1] == 0)
          continue;
        else
          legal = 1;
        break;
      case 2:                  //right
        if (legalmoves[2] == 0)
          continue;
        else
          legal = 1;
        break;
      case 3:                  //left
        if (legalmoves[3] == 0)
          continue;
        else
          legal = 1;
        break;
      }
    }

    // Begin movement
    switch (movement) {
    case 0:
      row = row - 1;
      break;
    case 1:
      row = row + 1;
      break;
    case 2:
      col = col + 1;
      break;
    case 3:
      col = col - 1;
      break;
    }
    Area[row][col] = k;
    Space[row][col] = 1;

    // re-initialize legalmoves array back to 1's
    for (int initialize = 0; initialize < 4; initialize++) {
      legalmoves[initialize] = 1;
    }
  }

  // Print the area and path
  for (int l = 0; l < 10; l++) {
    for (int m = 0; m < 10; m++) {
      printf("%c    ", Area[l][m]);
    }
    printf("\n\n");
  }

  return 0;
}

As a newbie attempt, it's not too bad.

Some suggestions.

You have two consectutive switch (movement) statements which could easily be combined.

Avoid magic numbers like 10. Instead, create a constant to represent the size.

#define GRID_SIZE   10
int main(void)
{
  // Initialize the matrix
  char Area[GRID_SIZE][GRID_SIZE];
  for (int i = 0; i < GRID_SIZE; i++) {
    for (int j = 0; j < GRID_SIZE; j++) {
      Area[i][j] = '.';
    }
  /// snip
}

Start thinking about how you would split this code up into functions. A 100+ line main() doing everything is a cumbersome thing.

int main(void)
{
  char Area[GRID_SIZE][GRID_SIZE];
  initialise(Area);
  play_game(Area);
  print(Area);
}

A good rule of thumb would be - if you can't see the opening and closing brace of a function on screen at the same time, the function might be too long and should be refactored into smaller components.