View Compilation Error

0_0_28546434_7755.c:2:1: error: unknown type name 'using'
 using namespace std;
 ^
0_0_28546434_7755.c:2:17: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'std'
 using namespace std;
                 ^
0_0_28546434_7755.c:8:9: error: unknown type name 'student'
 int cmp(student a,student b)
         ^
0_0_28546434_7755.c:8:19: error: unknown type name 'student'
 int cmp(student a,student b)
                   ^
0_0_28546434_7755.c: In function 'main':
0_0_28546434_7755.c:27:31: error: 'cmp' undeclared (first use in this function)
         stable_sort(stu,stu+n,cmp);
                               ^
0_0_28546434_7755.c:27:31: note: each undeclared identifier is reported only once for each function it appears in