I recommend either a Macbook Pro 15" 2017 model, though it might be a bit over your budget. macOS is great for development in C++, Swift, Python, and basically any language, though it mostly has an edge in C/C++ programming because it has a native compiler and doesn't have to run in an emulator like in Windows. Linux is also a great alternative for development because it is also Unix based like macOS, if you don't choose a Mac. In either case, I recommend getting a laptop with a large hard drive so you can dual boot into both Windows and a Unix/Unix-like OS of your choice. Here's what to look for:
A dual core Intel processor (preferably i5 or i7, though the performance difference between the two in dual core configuration is very minimal).
8-16GB of RAM (Anything more is overkill, anything less is too little)
512GB-1TB of Storage (preferably an SSD, as it's faster and potentially more reliable, but an HDD is fine too)
Discrete Graphics, Preferably a Geforce GTX 1050 Ti or AMD Radeon 540 or AMD Radeon Pro 540 or AMD Radeon Pro 550 (You could go 1060, but you'd be hard pressed to find a laptop with it in the $1400 price range, because most come with quad core i7 CPUs)
1080p, 1440p (2560*1440) or higher resolution display, Preferably glossy, because it's much nicer to stare at font on a higher DPI display for long hours than a grainy matte display
These are my two cents.