Need sample C code to encrypt and decrypt files using openssl

Question

I am writing code in Linux C. I need to encrypt and decrypt files using OpenSSL. Currently, Am uses the "des3 -e -nosalt -k 0123456789012345 -in inp_file -out out_file" system command for encryption and "des3 -d -nosalt -k 0123456789012345 -in inp_file -out out_file" system decryption. Where should I get sample code to do the same with the C API.

Answer 1

I would look here: http://www.openssl.org/docs/crypto/EVP_EncryptInit.html#EXAMPLES

and here: http://www.nlnetlabs.nl/downloads/publications/hsm/hsm_node17.html