system() take a look at
popen() popen(3): pipe stream to/from process - Linux man page
But before you do that, you should stop and think about whatever it is you think you need to sudo. As a general rule user level programs should not need to elevate privilege to perform work. That's a security hole waiting to be exploited. If you need to create a device file, load a kernel module or change permissions on a device file, that should be handled by the OS at boot time or device initialization time (eg a USB device being plugged in). Using sudo is almost certainly the Wrong Thing, and should only be considered when all other options have been exhausted.
Keep Calm and Carry On