View Compilation Error

0_0_38889245_3919.c: In function 'main':
0_0_38889245_3919.c:12:17: error: unknown type name 'hallo'
   12 |                 hallo world
      |                 ^~~~~
0_0_38889245_3919.c:13:17: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'for'
   13 |                 for(int i=0;i<len;i++){
      |                 ^~~
0_0_38889245_3919.c:13:29: error: 'i' undeclared (first use in this function)
   13 |                 for(int i=0;i<len;i++){
      |                             ^
0_0_38889245_3919.c:13:29: note: each undeclared identifier is reported only once for each function it appears in
0_0_38889245_3919.c:13:38: error: expected ';' before ')' token
   13 |                 for(int i=0;i<len;i++){
      |                                      ^
      |                                      ;
0_0_38889245_3919.c:13:38: error: expected statement before ')' token