以下程序的功能是根据输入的“y”(“Y”)与“n”(“N”),在屏幕上分别显示出“This is YES.”与“This NO.”。空白处需要填入的内容是 include<stdio.h> void YesNo(char ch) { switch(ch) { casey: caseY:printf('/n This is YES,/n'); casen: caseN:printf('/nThis is NO./n');}} main() { char ch; printf('/nEnter a char y,Yorn,N:'); ch=【 】; printf('ch;%c',ch); YesNo(ch);}