在c文件中附加二进制数据

I open a file in C and perform a CRC32 algorithm on the data. From this I get a checksum which I now want to append to the file so that the bit-code of the int is at the end of the bitcode of the file. But when I write the integer to the file all numbers are interpreted as chars and not the bitcode of the int is written. So I tried this: I open a file in C and perform a CRC32 algorith