You could use xmrig to mine cryptonight coins, but I don't think you will get great profits 
https://github.com/xmrig/xmrig
I recommend configuring xmrig to only utilize 50-60% of your CPU to not cause stability issues for your main GPU mining software and OS.
When I began mining, I had the CPUs of my rigs running on Monero but the profit was not worth mentioning and it caused stability issues especially when remotely administrating the rigs.
https://github.com/xmrig/xmrig
I recommend configuring xmrig to only utilize 50-60% of your CPU to not cause stability issues for your main GPU mining software and OS.
When I began mining, I had the CPUs of my rigs running on Monero but the profit was not worth mentioning and it caused stability issues especially when remotely administrating the rigs.
How much will you be making then for example with i3?
Expecting the i3 7100 to get 50-55H/s it would be 0.07$ in 24 hours. (power costs not included)