I am trying to produce a random walk solution but I get some strange results.
Here's the code :

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

int main (int argc, const char * argv[]) {
    // insert code here...
    char myArray[10][10];
	char letters[26] = {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'};
	int counter1 = 0;	//row
	int counter2 = 0;	//column
	int direction;	//variable to hold the direction of the next move
	int counter = 0;
	
	
	srand( (unsigned)time(NULL) );
	
	//fill myArray with dots
	for (int theCounter = 0; theCounter < 10; theCounter++)
	{
		for (int innerCounter = 0; innerCounter < 10; innerCounter++) {
			myArray[theCounter][innerCounter] = '.';
		}
	}
	
	myArray[0][0] = letters[counter];
	
	while (counter < 26) {
		//decide direction
		direction = rand() % 4;	//picks a random direction (0 - up, 1 - down, 2 - left, 3 - right)
		
		//up case
		if (direction == 0)	//bounders
		{
			if (counter1 == 0) {
				continue;
			}
		
			else if (myArray[counter1 - 1][counter2] == '.')
			{
				counter++;
				counter1--;
				myArray[counter1][counter2] == letters[counter];
			}//end if
		}//outer if


		//down case
		if (direction == 1)	//bounders
		{
			if (counter1 > 9)
			{
				continue;
			}
			else {
				counter++;
				counter1++;
				myArray[counter1][counter2] = letters[counter];
			}//end if
			
		}//end outer if
		
		//left case
		if (direction == 2)
		{
			if (counter2 == 0)
			{
				continue;
			}
		
			else if (myArray[counter1][counter2 - 1] == '.')
			{
				counter++;
				counter2--;
				myArray[counter1][counter2] == letters[counter];
			}//end if
		}//end outer if
		
		//right case
		if (direction == 3)	//bounders
		{
			if (counter1 > 8)
			{
				continue;
			}
			
			else if (myArray[counter1][counter2 + 1] == '.')
			{
				counter++;
				counter2++;
				myArray[counter1][counter2] == letters[counter];
			}//end inner if

		}//end outer if
		
	}//end while
	
	
	//print the grid
	for (int theCounter = 0; theCounter < 10; theCounter++)
	{
		for (int innerCounter = 0; innerCounter < 10; innerCounter++) {
			printf("%c", myArray[theCounter][innerCounter]);
		}
		printf("\n");
	}
}

One strange thing that I found duting debugging is that when direction = 3 the command after the counter2++ expression that assigns a value to an 2 dimensional array is never executed.
Why is this happening?
Thank you.

I made the classic mistake of == instead of =.
Sorry!!
:(

I made the classic mistake of == instead of =.
Sorry!!
:(

Happens to all of us. Thank-you for posting that you found the solution.

This is a solution but it does not work at all times and I can't find a logical flow in the code.
Any ideas?

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

int main (int argc, const char * argv[]) {
    // insert code here...
    char myArray[10][10];
	char letters[26] = {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'};
	int counter1 = 0;	//row
	int counter2 = 0;	//column
	int direction;	//variable to hold the direction of the next move
	int counter = 0;
	
	
	srand( (unsigned)time(NULL) );
	
	//fill myArray with dots
	for (int theCounter = 0; theCounter < 10; theCounter++)
	{
		for (int innerCounter = 0; innerCounter < 10; innerCounter++) {
			myArray[theCounter][innerCounter] = '.';
		}
	}
	
	myArray[0][0] = letters[counter];
	
	while (counter < 25) {
		//decide direction
		direction = rand() % 4;	//picks a random direction (0 - up, 1 - down, 2 - left, 3 - right)
		
		//up case
		if (direction == 0)	//bounders
		{
			if (counter1 == 0) {
				continue;
			}
		
			else if (myArray[counter1 - 1][counter2] == '.')
			{
				counter++;
				counter1--;
				myArray[counter1][counter2] = letters[counter];
			}//end if
		}//outer if


		//down case
		if (direction == 1)	//bounders
		{
			if (counter1 > 8)
			{
				continue;
			}
			else {
				counter++;
				counter1++;
				myArray[counter1][counter2] = letters[counter];
			}//end if
			
		}//end outer if
		
		//left case
		if (direction == 2)
		{
			if (counter2 == 0)
			{
				continue;
			}
		
			else if (myArray[counter1][counter2 - 1] == '.')
			{
				counter++;
				counter2--;
				myArray[counter1][counter2] = letters[counter];
			}//end if
		}//end outer if
		
		//right case
		if (direction == 3)	//bounders
		{
			if (counter2 > 8)
			{
				continue;
			}
			
			else if (myArray[counter1][counter2 + 1] == '.')
			{
				counter++;
				counter2++;
				myArray[counter1][counter2] = letters[counter];
				
				
			}//end inner if

		}//end outer if
		
	}//end while
	
	
	//print the grid
	for (int theCounter = 0; theCounter < 10; theCounter++)
	{
		for (int innerCounter = 0; innerCounter < 10; innerCounter++) {
			printf(" %c", myArray[theCounter][innerCounter]);
		}
		printf("\n");
	}
	
	return 0;
}

This is a solution but it does not work at all times and I can't find a logical flow in the code.
Any ideas?

Output key values during the execution to see if the program is behaving as you think it is. Try to pinpoint the area you have the flow...

Another try (not perfect yet) :

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

int main (int argc, const char * argv[]) {
    // insert code here...
    char myArray[10][10];
	char letters[26] = {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'};
	int counter1 = 0;	//row
	int counter2 = 0;	//column
	int direction;	//variable to hold the direction of the next move
	int counter = 0;
	
	
	srand( (unsigned)time(NULL) );
	
	//fill myArray with dots
	for (int theCounter = 0; theCounter < 10; theCounter++)
	{
		for (int innerCounter = 0; innerCounter < 10; innerCounter++) {
			myArray[theCounter][innerCounter] = '.';
		}
	}
	
	myArray[0][0] = letters[counter];
	
	while (counter < 25) {
		//decide direction
		direction = rand() % 4;	//picks a random direction (0 - up, 1 - down, 2 - left, 3 - right)
		
		if (counter1 == 0 && counter2 > 0)
		{
			if (myArray[counter1 + 1][counter2] != '.' && myArray[counter1][counter2 + 1] != '.' && myArray[counter1][counter2 - 1] != '.')
				break;
		}//first side
		
		else
		
		if (counter1 > 0 && counter2 == 0)
		{
			if (myArray[counter1 - 1][counter2] != '.' && myArray[counter1 + 1][counter2] != '.' && myArray[counter1][counter2 + 1] != '.')
				break;
		}//second side
		
		else
		
		{
			if (myArray[counter1 + 1][counter2] != '.' && myArray[counter1 - 1][counter2] != '.' && myArray[counter1][counter2 - 1] != '.' && myArray[counter1][counter2 + 1] != '.')
			{
				printf("!");
				break;
			}
		}
			
			
		//up case
		if (direction == 0)	//bounders
		{
			if (counter1 == 0) {
				continue;
			}
		
			else if (myArray[counter1 - 1][counter2] == '.')
			{
				counter++;
				counter1--;
				myArray[counter1][counter2] = letters[counter];
			}//end if
		}//outer if


		//down case
		if (direction == 1)	//bounders
		{
			if (counter1 > 8)
			{
				continue;
			}
			else {
				counter++;
				counter1++;
				myArray[counter1][counter2] = letters[counter];
			}//end if
			
		}//end outer if
		
		//left case
		if (direction == 2)
		{
			if (counter2 == 0)
			{
				continue;
			}
		
			else if (myArray[counter1][counter2 - 1] == '.')
			{
				counter++;
				counter2--;
				myArray[counter1][counter2] = letters[counter];
			}//end if
		}//end outer if
		
		//right case
		if (direction == 3)	//bounders
		{
			if (counter2 > 8)
			{
				continue;
			}
			
			else if (myArray[counter1][counter2 + 1] == '.')
			{
				counter++;
				counter2++;
				myArray[counter1][counter2] = letters[counter];
				
				
			}//end inner if

		}//end outer if
		
	}//end while
	
	
	//print the grid
	for (int theCounter = 0; theCounter < 10; theCounter++)
	{
		for (int innerCounter = 0; innerCounter < 10; innerCounter++) {
			printf(" %c", myArray[theCounter][innerCounter]);
		}
		printf("\n");
	}
	
	return 0;
}

The program must randomly "walk" from element to element, always going up, down, left or right by one element.
The elements visited by the program will be labeled with the letters A through Z, in the order visited.
If all four directions are blocked, the program must terminate.

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