View Compilation Error

0_0_13580414_20448.cpp:10:5: error: expected unqualified-id before 'this'
 int this=0;
     ^
0_0_13580414_20448.cpp: In function 'void dfs(char)':
0_0_13580414_20448.cpp:20:15: error: invalid use of 'this' in non-member function
     for(i=0;i<this;i++)
               ^
0_0_13580414_20448.cpp: In function 'int main()':
0_0_13580414_20448.cpp:37:13: error: invalid use of 'this' in non-member function
         all[this].start=str[0];
             ^
0_0_13580414_20448.cpp:38:13: error: invalid use of 'this' in non-member function
         all[this++].end=str[strlen(str)-1];
             ^
0_0_13580414_20448.cpp:43:17: error: invalid use of 'this' in non-member function
             all[this].start=str[0];
                 ^
0_0_13580414_20448.cpp:44:17: error: invalid use of 'this' in non-member function
             all[this++].end=str[strlen(str)-1];
                 ^
0_0_13580414_20448.cpp:51:9: error: invalid use of 'this' in non-member function
         this=0;
         ^