I can't figure out why it works half the time

Question

My own minesweeper I am trying to make

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


int randNum(int minimum, int maximum);
int checkSurroundings(int x, int y);


//settings:
int diffi = 3;                        //how frequently mines show up, 1/n
const int width = 10, height = 10;    //height and width of the board
int state[10][10];                    //couldn't make it dynamic with W and H,
                                      //it gives me an error that it is at file scope
int mineshape = 'X';

//the main
void main(){

    srand(time(NULL));      //seeds the randomizer once at the start

    state[height][height];

    for(int y = 0; y < height; y++){

        printf("/ ");

        for(int x = 0; x < width; x++){

            state[x][y] = randNum(0, diffi);

            //assigns the board values accordingly
            if (state[x][y] == diffi){

                state[x][y] = mineshape;
            }
            else{

                state[x][y] = checkSurroundings(x, y);
            }

            printf("%c ", state[x][y]);
        }

        printf("/  %d\n",y + 1);
    }
}

the RNG I used to generate mine cells: (I don't think this has anything to do with the problem), I got it from google

int randNum(int minimum, int maximum){

    int result = 0, low_num = 0, hi_num = 0;

    if (minimum < maximum){

        low_num = minimum;
        hi_num = maximum + 1;
    }
    else{

        low_num = maximum + 1;
        hi_num = minimum;
    }

    result = (rand() % (hi_num - low_num)) + low_num;

    return result;
}

this was my implementation to loop over the surrounding cells and check them:

/*int checkSurroundings(int x, int y){

    int mines = 0, i, j;

    for(j = y-1; j <= y+1; j++){

        for(i = x-1; i <= x+1; i++){

            if(state[i][j] == mineshape){

                mines++;
            }
        }
    }

    return mines + 48;
}
*/

here I used a manual code to check surroundings, marked the broken instructions with x in the comment: both implementations have the same problem with checking all the cells around.

int checkSurroundings(int x, int y){

    int mines = 0, i, j;

    if(state[x-1][y-1] == mineshape){   //top left
        mines++;
    }
    if(state[x][y-1] == mineshape){     //top
        mines++;
    }
    if(state[x+1][y-1] == mineshape){   //top right
        mines++;
    }

    if(state[x-1][y] == mineshape){     //left
        mines++;
    }
    if(state[x+1][y] == mineshape){     //x right
        mines++;
    }

    if(state[x-1][y+1] == mineshape){   //x bottom left
        mines++;
    }
    if(state[x][y+1] == mineshape){     //x bottom
        mines++;
    }
    if(state[x+1][y+1] == mineshape){   //x bottom right
        mines++;
    }

    return mines + 48;
}

it for some reason doesn't check the cells at the right, bottom-left, bottom, bottom-right cells around the current cell, and I can't figure it out. I am new to coding, started learning C around 2 months ago.