View Compilation Error

0_0_29136452_8185.c: In function 'main':
0_0_29136452_8185.c:14:33: error: 'num' undeclared (first use in this function)
   arr1=(int*)malloc(sizeof(int)*num);
                                 ^
0_0_29136452_8185.c:14:33: note: each undeclared identifier is reported only once for each function it appears in