Battleship game in C - c

Question

I have been coding the battleship game in C but I have a few problems. First of all, I would like to have a counter for the "hit and sunk" ships (it is coded, but it doesn't seem to work, after you hit a ship, it always prints 1), and therefore, this doesn't end the program when all ships are sunk. Here is my code for the main and "shoot" functions:
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define rows 5
#define columns 5
int mainint main(){
srand(time(NULL));
int grid[rows][columns], attemps=0, ships;
int sunk;
printf("Let's play the battleship game!\n");
printf("You have 20 tries.\n");
printf("Enter the number of ships: ");
scanf("%d",&ships);
prepare_grid(grid); //Prepare grid with items of value -1
gen_ships(grid,ships); //Generate random ships surrounded by water (value 1)
print_grid(grid); //Print grid without showing the generated ships (all items will be "~" meaning "undiscovered water).
sunk=0;
for (int a=0;a<20;a++){
shoot(grid,sunk,ships);
attemps++;
print_grid(grid);
printf("\nAttemps: %d\n",attemps);
}
print_secret_grid(grid); //Print final grid, showing all sunk ships and positions shot
return 0;
}
void shoot(int grid[rows][columns], int sunk, int ships) {
int x, y;
printf("\nLine --> ");
scanf("%d", &x);
printf("Column --> ");
scanf("%d", &y);
do {
if (grid[x-1][y-1] == 1) {
grid[x-1][y-1] = 2; //We assign value 2 because we want to print only the ones the user hits, it will print X which means "hit and sunk".
sunk++;
printf("\nHit and sunk\n");
printf("Sunk ships:%d \n\n", sunk);
} else if (grid[x - 1][y - 1] == -1) { //It will print "*" which means "discovered water".
grid[x - 1][y - 1] = 0;
printf("\nMiss\n\n");
}
}while (sunk=!ships);
}

Answer 1

When using a function call in C, the value is passed by copy. This means that
int value = 0;
function(value);
printf("%d\n", value);
will always print the value 0, even if the function reads like
void function(int value) {
value++;
}
because within the function function, a copy of the int value is being incremented.
To fix this, pass a copy of the memory location of value, and then increment the number stored at that location.
int value = 0;
function(&value);
with
void function(int* value) {
(*value)++;
}

Answer 2

sunk is passed by value. It needs to be passed by reference. Send the pointer to sunk, and receive sunk as a pointer in the shoot function.
Alternatively, make sunk a global variable and increment it, although I'd not suggest this for bigger programs!
Read more about passing by value and passing by reference to prevent such things from happening in the future! :D