View Compilation Error

0_0_21504884_27956.c:11:9: error: unknown type name 'NODE'
 int cmp(NODE x,NODE y)
         ^
0_0_21504884_27956.c:11:16: error: unknown type name 'NODE'
 int cmp(NODE x,NODE y)
                ^
0_0_21504884_27956.c: In function 'main':
0_0_21504884_27956.c:37:26: error: 'cmp' undeclared (first use in this function)
         sort(girl,girl+n,cmp);
                          ^
0_0_21504884_27956.c:37:26: note: each undeclared identifier is reported only once for each function it appears in