Opening Files in C - c

Question

Full Edit:
I am getting frustrated, I don't know what am I doing wrong in here
I still have so many stuff to do in the code but I can't even open a file to continue my work.
#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
void main()
{
char letter;
FILE *fp;
fp=fopen("‪‪‪C:\\Users\\LENOVO\\Desktop\\data.txt","r");
if(fp==NULL)
{
printf("error");
getch();
exit(1);
}
while(fscanf(fp,"%d",&letter)!=EOF)
putchar(letter);
getch();
fclose(fp);
}‪
Picture of the path: http://imgur.com/a/YwFYy
Still prints error

Answer 1

Ok, firstly let's take a look at your file path. There are two ways to acces a file from your local storage:
relative addresses if the file has the same root folder as your application
absolute addresses if the file is in a determined place on your machine's storage
I see that you are trying to use an absolute address to read from your file. Your path is correct but you have to take care about string formatting in C because the \ character could be interpreted as something else.
I would suggest to use this instead ( double back-slash )
input=fopen("‪C:\\Users\\LENOVO\\Desktop\\data.txt","r");
This will prevent string formatting interpretations.
Secondly, EOF is just a predefined macro constant and i think it is equal to -1 so your while(! (-1) ) code is not a good ideea for reading until the end of the file.
In order to read from a file until you reach the its end i would consider this property of fscanf() :
fscanf() returns EOF when it reaches the end of the file.
while(fscanf(input,"%ch",&letter) != EOF) {
putchar(letter);
}
This way of reading from a file should do the job.

Answer 2

To read everything from a text file and store its contents into a buffer:
First, you should count how many characters there are in the text file:
size_t get_file_len(FILE *fp)
{
size_t num = 0;
while (fgetc(fp) != EOF)
num++;
return (fseek(fp, 0, SEEK_SET) == 0 ? num : 0);
}
Then allocate memory for a buffer large enough and read all the characters:
char *load_text(const char *path)
{
char *buf = NULL;
FILE *fp = NULL;
size_t num = 0;
size_t i = 0;
int c = 0;
/* open the file in text mode */
fp = fopen(path, "r");
if (!fp)
return NULL;
/* if the file was empty or if an error occurred, return error */
if ((num = get_file_len(fp)) == 0) {
fclose(fp);
return NULL;
}
buf = malloc(num + 1);
if (!buf) {
fclose(fp);
return NULL;
}
while ((c = fgetc(fp)) != EOF)
buf[i++] = (char)c;
/* ensure that the string is null-terminated */
buf[i] = '\0';
fclose(fp);
return buf;
}
Also, in C, all escape sequences begin with a '\' (backslash), so if you wanted to write a backslash in a string or a char you should write it as a '\\' (double backslash):
input=fopen("‪C:\\Users\\LENOVO\\Desktop\\data.txt","r");

Answer 3

pretty simple here :
while(!feof(input)){
fscanf(input,"%c",&letter);
putchar(letter);
}
and remember to close file using fclose(input);