View Compilation Error

In file included from 0_0_32149453_21661.cpp:1:0:
0_0_32149453_21661.cpp: In function 'int main()':
0_0_32149453_21661.cpp:6:18: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
  while(gets(ch)!=EOF)
                  ^
0_0_32149453_21661.cpp:17:22: error: 'ch0' was not declared in this scope
    printf("%c %c %c",ch0,ch1,ch2);
                      ^
0_0_32149453_21661.cpp:17:26: error: 'ch1' was not declared in this scope
    printf("%c %c %c",ch0,ch1,ch2);
                          ^
0_0_32149453_21661.cpp:17:30: error: 'ch2' was not declared in this scope
    printf("%c %c %c",ch0,ch1,ch2);
                              ^