esp8266 board c code example

Example 1: install nodemcu in arduino

Go to file -> preferances. 	
Add below link to additional board manager. 
LINK: http://arduino.esp8266.com/stable/package_esp8266com_index.json
Tools -> Boards Manager 
Search for ESP and install esp8266

Example 2: esp8266 arduino

Serial.printf("Wi-Fi mode set to WIFI_STA %s\n", WiFi.mode(WIFI_STA) ? "" : "Failed!");