Accept string for a finite automata using automata from txt file.

DFA.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

int main()
{
    FILE *fp;
    int init, *FS, **FA, i, j, col, row, fs, r, c;
    char *str, temp[50];
    
    fp = NULL;
    FA = NULL;
    FS = NULL;
    str = NULL;
    
    fp = fopen("automata.txt", "r");

    fscanf(fp, "%d", &init);
    fgets(temp, sizeof(char)*50, fp);
    fgets(temp, sizeof(char)*50, fp);

    str = temp;
    i = 0;
    while(*str != '\0')
    {
        FS = (int *) realloc(FS, sizeof(int)*(i+1));
        sscanf(str, "%d", &FS[i++]);

        str++;
        while(isdigit(*str))
        {            
            str++;
        }
        
        while(isspace(*str))
            str++;
    }
    
    fs = i;
    
    fgets(temp, sizeof(char)*50, fp);
    str = temp;
    i= 0;

    FA = (int **) malloc(sizeof(int *)*1);
    FA[0] = NULL;
    while(*str != '\0')
    {
    	FA[0] = (int *)realloc(FA[0], sizeof(int)*(i+1));
        sscanf(str, "%d", &FA[0][i++]);

        str++;
        while(isdigit(*str))
            str++;
        while(isspace(*str))
            str++;
    }
    row = 1;
    col = i;
    while(!feof(fp))
    {
    	FA = (int **) realloc(FA, sizeof(int *)*(row+1));
    	FA[row] = NULL;
        fgets(temp, sizeof(char)*50, fp);
        
        str = temp;
        i= 0;
        while(*str != '\0')
        {
        	FA[row] = (int *)realloc(FA[row], sizeof(int)*(i+1));
            sscanf(str, "%d", &FA[row][i++]);

            str++;
            while(isdigit(*str))
                str++;
            while(isspace(*str))
                str++;
        }
        row++;
    }
    
    
    
    printf("Initial State: %d\n", init);
    printf("Final states: ");
    
    for(i = 0; i < fs; i++)
        printf("%d ", FS[i]);
    
    printf("\nInput Table:\n");
    
    for(i = 0; i < row; i++)
    {
        for(j = 0; j < col; j++)
        {
            printf("%d\t", FA[i][j]);
        }
        printf("\n");
    }
    
    while(1)
    {
    	printf("Enter the string to be validated using the Finite Automata (\"q\" to quit): ");
    	scanf("%s", temp);
        
    	if(strcmp(temp, "q") == 0)
    		break;
        
    	str = temp;
    	r = 0;
        
    	while(*str != '\0')
    	{
    		c = tolower(*str) - 97;	
            
    		if((c >= col) || (c < 0))
    		{
                printf("%d", c);
    			printf("Invalid input symbol!\n");
    			c = -1;
    			break;
    		}
            
    		if(FA[r][c] != -1)
    		{
    			r = FA[r][c];
    			str++;
    		}
            
    		else
    		{
    			printf("Input symbol unexpected!\n");
    			c = -1;
    			break;
    		}
            
    	}
        
    	if(c == -1)
    		continue;
    	for(i = 0; i < fs; i++)
    		if(r == FS[i])
    		{
    			printf("String validated.\n");
    			break;
    		}
        
    	if(i == fs)
    		printf("String accepted(non-final state).\n");
    };
    
    return 0;
}

/* input.txt -
0
3
1 -1 -1
2 1 -1
-1 -1 3
-1 -1 -1
*/