View Compilation Error

0_0_15009226_26023.cpp:14:12: error: 'MAX' was not declared in this scope
 int father[MAX];
            ^
0_0_15009226_26023.cpp: In function 'void BuildTree(int, int, int)':
0_0_15009226_26023.cpp:23:9: error: 'father' was not declared in this scope
         father[left]=i;
         ^
0_0_15009226_26023.cpp: In function 'int main()':
0_0_15009226_26023.cpp:73:9: error: 'father' was not declared in this scope
    node[father[i]].value = igrade;
         ^
0_0_15009226_26023.cpp:87:10: error: 'father' was not declared in this scope
     node[father[a]].value = b;
          ^