View Compilation Error

0_0_34134176_21296.cpp: In function 'int main()':
0_0_34134176_21296.cpp:6:14: error: cannot convert 'int*' to 'char*' for argument '1' to 'char* gets(char*)'
  while(gets(a)!=NULL)
              ^
0_0_34134176_21296.cpp:9:25: error: cannot convert 'int*' to 'const char*' for argument '1' to 'size_t strlen(const char*)'
   for(int i=0;i<strlen(a);i++)
                         ^