POJ3981字符串替换

#include<stdio.h>int main(void){char ch1,ch2,ch3;while((ch1=getchar())!=EOF){if(ch1=='y'){if((ch2=getchar())=='o'){if((ch3=getchar())=='u'){printf("we");}else printf("yo%c",ch3);}else printf("y%c",ch2);}else putchar(ch1);}}