c program stops executing without any errors - c

Question

in function calcdist() program stops running sometimes.
is it my computer or my code?
The program takes size for a 2d array (a square parking slot) then take the cars, after that finds best slot for our car.
best slot must have the largest distance to the nearest point.
distance is calculating by using manhatten distance.
most of the printf s for finding where the problem is.
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#define CAPACITY 50
int calcdist(int x, int y, int carnum[][CAPACITY], int size);
int main ()
{
int size, numofcars, x, y, mindist = 0, bestx = 0, besty = 0;
printf("Size: ");
scanf("%d", &size);
int carnum[size][size];
printf("Cars: ");
scanf("%d", &numofcars);
for(int i = 0; i < size; i++){
for(int j = 0; j < size; j++){
carnum[i][j] = 0;
}
}
for(int i = 0; i < numofcars; i++){
printf("Locations: ");
scanf("%d %d", &x, &y);
carnum[x - 1][y - 1] = 1;
}
for(int i = 0; i < size; i++){
for(int j = 0; j < size; j++){
printf("%d ",carnum[i][j]);
}
printf("\n");
}
printf("carnum[3][0]: %d\n",carnum[3][0]);
for(int i = 0; i < size; i++){
for(int j = 0; j < size; j++){
if(carnum[i][j] == 0){
printf("hi ");
if(mindist < calcdist(i, j, carnum, size)){
mindist = calcdist(i, j, carnum, size);
bestx = i + 1;
besty = j + 1;
printf("mindist is %d\n", calcdist(i, j, carnum, size));
}
}
}
}
printf("Best Slot Found In: %d %d\n", bestx, besty);
return 0;
}
int calcdist(int x, int y, int carnum[][CAPACITY], int size){
int dist = size * 2;
printf("x is: %d y is : %d\n", x, y);
for(int i = 0; i < size; i++){
for(int j = 0; j < size; j++){
printf("i is: %d j is : %d ", i, j);
if((carnum[i][j] == 1) && (dist > (abs(x - i) + abs(y - j) ))){
dist = abs(x - i) + abs(y - j);
}
printf("i is: %d j is : %d\n", i, j);
}
}
return dist;
}

Answer 1

/****** && (logical and) not & (unary operator) ******/
if((carnum[i][j] == 1) && (dist > (abs(x - i) + abs(y - j) )))