用c 获取文件MD5值的实现方法

???C???????MD5?,???????MD5?,??md5deep?OpenSSL??GNU md5sum?????OpenSSL???,????????????:

#include 
#include 
#define MAX_BUFFER_SIZE 1024
int main() {
char filename[MAX_BUFFER_SIZE];
unsigned char c[MD5_DIGEST_LENGTH];
int i;
printf("??????MD5????:");
fgets(filename, MAX_BUFFER_SIZE, stdin);
// ??filename?????
for (i = 0; i < MAX_BUFFER_SIZE; i++) {
if (filename[i] == '\n') {
filename[i] = '\0';
break;
}
}
FILE *file = fopen(filename, "rb");
if (!file) {
printf("?????? %s\n", filename);
return 1;
}
MD5_CTX md5Context;
MD5_Init(&md5Context);
unsigned char buffer[MAX_BUFFER_SIZE];
int bytesRead;
while ((bytesRead = fread(buffer, 1, MAX_BUFFER_SIZE, file)) != 0) {
MD5_Update(&md5Context, buffer, bytesRead);
}
MD5_Final(c, &md5Context);
printf("MD5 ??:");
for (i = 0; i < MD5_DIGEST_LENGTH; i++) {
printf("x", c[i]);
}
printf("\n");
fclose(file);
return 0;
}

?????????,????????MD5????,??????,???????????MD5????,????????OpenSSL?,????????????:

gcc -o md5 md5.c -lssl -lcrypto

??,md5.c???????????,-lssl -lcrypto?????OpenSSL??