I've find this solution for the problem and it worked in my case.
char *args[] = {"/usr/bin/wget", "-P","./Folder", "http://www.google.com", (char *) 0 };
execv("/usr/bin/wget", args);
And another solution to this is to directly run the command with system function like:
system(wget -P ./Folder http://www.google.com)