View Compilation Error

32142_0_30627.cpp: In function `int main()':
32142_0_30627.cpp:3: error: `MAXN' undeclared (first use this function)
32142_0_30627.cpp:3: error: (Each undeclared identifier is reported only once for each function it appears in.)
32142_0_30627.cpp:6: error: `scanf' undeclared (first use this function)
32142_0_30627.cpp:6: error: `EOF' undeclared (first use this function)
32142_0_30627.cpp:11: error: `a' undeclared (first use this function)
32142_0_30627.cpp:16: error: `printf' undeclared (first use this function)
32142_0_30627.cpp:25: error: `malloc' undeclared (first use this function)
32142_0_30627.cpp:40: error: `free' undeclared (first use this function)