Splitting and modifying a string from text file in C - c

Question

In a school project I am making a Caesar's Cipher. The requirements I have to meet are the following: I need to read text from a text file, store it into a bi-dimensional array of strings with a maximum of 81 characters per line(80 useful + '\0') and 1000 lines, and then modify the content in order to cipher or decipher it. What if in a single line of text from the file I has more than 80 useful characters? I thought about making it read in a way that each space it reads transforms it into a '\0' and changes line in the array but I don't know if I can do it with fgets, instead of fgetc as I was doing it.
This is what I have right now:
int lerficheiro(char * texto[MAXLINHAS][MAXCARPORLINHA])
{
char caractere;
FILE * fp;
fp = fopen("tudomaiusculas.txt", "r");
if(fp==NULL)
{
printf("Erro ao ler ficheiro.");
return (-1);
}
for(int linha = 0; linha < MAXLINHAS; linha++)
{
for(int coluna = 0; coluna < MAXCARPORLINHA; coluna++)
{
caractere = fgetc(fp);
if(caractere == ' ') caractere = '\0'; break;
if(caractere == '\n') caractere = '\0'; break;
if(caractere < 'A' || caractere > 'Z')
{
printf("Erro ao ler, o ficheiro não contem as letras todas
maiusculas");
return (-1);
}
* texto[linha][coluna] = caractere;
}
}
}

Answer 1

Initialize your array to 0 and make use of the fact that you select how many bytes you are reading using fgets. Just check the return value of fgets to see if you've reached the end of the file.
Also note that you should not need to have your result array as a pointer, since array already are pointers (EDIT to mirror #user3629249 suggestions)
EDIT2: Edited code to take into account the new-line problem. Alo removed the -1 that was causing 79 char lines instead of 80
#include <stdio.h>
#include <string.h>
#define MAX_LINES 8000
#define HSIZE 81
int parse_file( FILE * inp_file, char res[MAX_LINES][HSIZE])
{
int l = 0;
int len = HSIZE;
while( fgets( res[l]+(HSIZE-len), len, inp_file ))
{
len = HSIZE - strlen( res[l]);
if( len <= 1)
{
l++;
len = HSIZE;
}
}
}
int main()
{
char parsed_file[MAX_LINES][HSIZE] = {0};
FILE * inp_file;
inp_file = fopen( "file_to_parse.txt", "r");
if( inp_file == NULL)
{
printf( "Failed to read input file...\n");
return 1;
}
parse_file( inp_file, parsed_file);
fclose( inp_file);
for( int i=0; parsed_file[i][0] != 0; i++)
printf( "line %04d: %s\n", i+1,parsed_file[i]);
return 0;
}
If you want you could also replace the new line in your parsed_file with something like this
char *pos;
while( (pos = strchr( line, '\n'))
*pos = ' ';
With test file:
This is a random file that I'm testing out for the pure randomness of random files.
Still reading, m'kay man lets get going!!!!!!!!!!! So last day the craziest thing happened, let me tell you about it....
and output
line 0001: This is a random file that I'm testing out for the pure randomness of random fil
line 0002: es.
Still reading, m'kay man lets get going!!!!!!!!!!! So last day the craziest
line 0003: thing happened, let me tell you about it....
Take care that the printf will still print the newline character