Getting every other line empty on output - c

Question

I have a problem with getting every other line empty on output with this code. The desired output is: http://paste.ubuntu.com/1354365/
While I get: http://paste.ubuntu.com/1356669/
Does anyone have an idea of why I'm getting these empty lines on every other line?
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
FILE *fp;
FILE *fw;
int main(int argc, char *argv[]){
char buffer[100];
char *fileName = malloc(10*sizeof(char));
char **output = calloc(10, sizeof(char*));
char **outputBuffer = calloc(10, sizeof(char*));
fw = fopen("calvin.txt", "w+");
for(int y = 0; y < 6; y++){
for(int i = 0; i < 10; i ++)
{
output[i] = malloc(100);
}
for(int x = 0; x < 12; x++){
sprintf(fileName,"part_%02d-%02d", x, y);
fp = fopen(fileName, "rb");
if(fp == NULL)
{
printf("Kan ikke åpne den filen(finnes ikke/rettigheter)\n");
}
else if(fp != NULL){
memset(buffer, 0, 100);
for(int i = 0; i < 10; i++){
outputBuffer[i] = malloc(100);
}
fread(buffer, 1, 100, fp);
for(int i = 0; i < 100; i++){
if(buffer[i] == '\0')
{
buffer[i] = ' ';
}
else if(buffer[i] == '\n')
{
buffer[i] = ' ';
}
}
for(int i = 0; i < 10; i++) {
strncpy(outputBuffer[i], buffer + i * 10, 10);
strncat(output[i], outputBuffer[i]+1, 11);
}
}
}
for(int i = 0; i < 10; i++){
printf("%s\n", output[i]);
}
}
fclose(fp);
free(fileName);
}

Answer 1

You are not reading correcting from the file. On the first image in the beginning you have:
o ""oo " o o o
on the second
""oo o o o
That does not make a lot of sense because it is the first line. It is not related to empty lines since we are talking about the first line.
It seems that you are reading -2 characters from the left so " prints over o the other " on the ' ' ect..
Try this away, may not be the most efficient solution:
int read(char *file)
{
FILE *fp = NULL;
int size = 0, pos = 0,i;
fp = fopen(file,"r");
if (!fp) return 0;
for(; ((getc(fp))!=EOF); size++); // Count the number of elements in the file
fclose(fp);
char buffer[size];
fp = fopen(file,"r");
if (!fp) return 0;
while((buffer[pos++]=getc(fp))!=EOF); // Saving the chars into the buffer
for(i = 0; i < pos; i++) // print them.
printf("%c",buffer[i]);
fclose(fp);
return 1;
}

Answer 2

This part seems problematic:
strncpy(outputBuffer[i], buffer + i * 10, 10);
strncat(output[i], outputBuffer[i]+1, 11);
1) Why is it necessary to use the extra outputBuffer step?
2) You know that strncpy() isn't guaranteed to null-terminate the string it copies.
3) More significantly, output[i] hasn't been initialized, so strncat() will concatenate the string after whatever junk is already in there. If you use calloc() instead of malloc() when creating each output[i], that might help. It's even possible that your output[i] variables are what hold your extra newline.
4) Even if initialized to an empty string, you could easily overflow output[i], since you're looping 12 times and writing up to 11 characters to it. 11 * 12 + 1 for the null terminator = 133 bytes written to a 100-byte array.
In general, unless this is a class assignment that requires use of malloc(), I don't understand why you aren't just declaring your variables once, at the start of the program and zeroing them out at the start of each loop:
char fileName[10];
char output[10][100];
char outputBuffer[10][100];
And, as stated by others, your allocating a bunch of memory and not trying to free it up. Allocate it once outside of your loop or just skip the allocation step and declare them directly.