Programming

char *FILEREAD(const char *FILENAME)
{
    static char READBUFFER[15001] = "";
READBUFFER[0] = '\0'; // try to solve the problem but this will not

    FILE *FILE1 = fopen(FILENAME, "r");

    fread(READBUFFER, 1, 15000, FILE1);

    fclose(FILE1);

    return READBUFFER;
}

int main(void)
{
printf("%s\n", FILEREAD("file1.txt")); // file content is: "wwwww" and FILEREAD outputs "wwwww"
printf("%s\n", FILEREAD("file2.txt")); // file content is: "aaa" and FILEREAD outputs "aaaww"

return 0;
}

READBUFFER[0]='w'
READBUFFER[1]='w'
READBUFFER[2]='w'
READBUFFER[3]='w'
READBUFFER[4]='w'
READBUFFER[5]='\0'

READBUFFER[0]='a'
READBUFFER[1]='a'
READBUFFER[2]='a'
READBUFFER[3]='w'
READBUFFER[4]='w'
READBUFFER[5]='\0'

size_t n;
...
n = fread(...)
READBUFFER[n]='\0';