Why fread() giving extra garbage value-CodePudding

I am reading content of a file and and trying to print it, but it is giving extra garbage value.

#define _CRT_SECURE_NO_DEPRECATE
#include <stdio.h>
#include <stdlib.h>

int main() {
    long length;
    char* content;
    FILE *file = fopen("text.txt", "r");
    fseek(file, 0, SEEK_END);
    length = ftell(file);
    fseek(file, 0, SEEK_SET);
    content = (char *)malloc(length);
    fread(content, 1, length, file);
    printf("%s\n", content);
    return 0;
}

Maybe I have to null terminate content[length] = '\0';?

The more \n newline characters the file has at the end, the more garbage I get.

Any solution, except using calloc?

CodePudding user response：

If that is MSVC (clued by #define _CRT_SECURE_NO_DEPRECATE) then the file mode is probably text by default, and all the CR-LF pairs will be shrunk to a single LF when you read it. Getting the file size does not take that into account. Use the number of characters actually read to terminate the string.

content = malloc(length   1);           // room for terminator
size_t bytes = fread(content, 1, length, file);
content[bytes] = '\0';

CodePudding user response：

The file content does not end with the null char. Your should reset the allocated memory buffer with 0, since it's unknown how many bytes will be read.

content = (char *)malloc(length   1);
memset(content, 0, length   1);
fread(content, 1, length, file);

Or you should set the data length while printing

length = fread(content, 1, length, file);
printf("%.*s\n", length, content);

See Is there a way to specify how many characters of a string to print out using printf()?