View Compilation Error

0_0_12292313_30265.c:1:20: iostream: No such file or directory
0_0_12292313_30265.c:2:17: cstdio: No such file or directory
0_0_12292313_30265.c:3:18: cstdlib: No such file or directory
0_0_12292313_30265.c: In function `Creat':
0_0_12292313_30265.c:15: error: `NULL' undeclared (first use in this function)
0_0_12292313_30265.c:15: error: (Each undeclared identifier is reported only once
0_0_12292313_30265.c:15: error: for each function it appears in.)
0_0_12292313_30265.c: In function `Insert':
0_0_12292313_30265.c:21: error: `NULL' undeclared (first use in this function)
0_0_12292313_30265.c: In function `PreOrder':
0_0_12292313_30265.c:34: error: `NULL' undeclared (first use in this function)
0_0_12292313_30265.c: In function `main':
0_0_12292313_30265.c:48: error: `EOF' undeclared (first use in this function)
0_0_12292313_30265.c:50: error: `NULL' undeclared (first use in this function)