char « write « C File Q&A

1. Why must we convert everything to a char* when we write it to a file?    stackoverflow.com

Out of curiosity, why are we converting something to a char* when we write it to a ( binary ) file?

2. EXC_BAD_ACCESS writing char to txt file    stackoverflow.com

#include <stdio.h>
int main (int argc, const char * argv[])

{
    FILE *fp;
    fp=fopen("/Users/--------/Desktop/C.txt", "w");
    putc("C", "/Users/-------/Desktop/C.txt");
    fclose(fp);
}

3. How to Read from .txt file & Write into .bin file w/o weird char at the end    bytes.com

I am trying to create a .bin file of records from a .txt file. Initially the records are stored in a text file and I want to Read from the .txt file and Write to the .bin file. This is the C++ code. The result write exactly but it has funny-looking unwanted characters attached at the end of the .bin file. ...