/in/foo.cc:9:6: error: stray '\' in program
 s[i]=\0;
      ^
/in/foo.cc: In function 'void insert(char*)':
/in/foo.cc:23:4: warning: array subscript has type 'char' [-Wchar-subscripts]
 s[k]=s[k+1];
    ^
/in/foo.cc:24:4: warning: array subscript has type 'char' [-Wchar-subscripts]
 s[j]=',';
    ^
/in/foo.cc: At global scope:
/in/foo.cc:28:11: error: '::main' must return 'int'
 void main()
           ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:33:13: error: too many arguments to function 'void insert(char*)'
 insert(s,num);
             ^
/in/foo.cc:15:6: note: declared here
 void insert(char s[])
      ^~~~~~