A free program for Android, by Nu-Kob.

If you often forget your WiFi password or your phone can’t remember your WiFi name (SSID) and password, NeverForget WiFi AutoConnect is the perfect app.If your phone can’t remember your WiFi name (SSID), password and security mode, our app will automatically connect to remembered WiFi when available. You won’t have to connect manually every time. And we’ll also restore the WiFiWiFi configuration if it gets lost.

This application also has an option where you can enable or disable auto restore WiFi configuration function so that the next time someone loses their credentials, they can easily reset them by pressing one button again.