View Compilation Error

In file included from 0_0_36816371_28444.cpp:1:0:
0_0_36816371_28444.cpp: In function 'int main()':
0_0_36816371_28444.cpp:8:21: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
 while(gets(Cipher)!=EOF)
                     ^
0_0_36816371_28444.cpp:10:18: error: 'strlen' was not declared in this scope
 len=strlen(Cipher);
                  ^
0_0_36816371_28444.cpp:12:25: error: 'strcmp' was not declared in this scope
 if(strcmp(Cipher,"START")==0)
                         ^