View Compilation Error

0_0_37008771_24494.cpp:1:1: error: expected unqualified-id before '>' token
 >
 ^
0_0_37008771_24494.cpp: In function 'bool place(int)':
0_0_37008771_24494.cpp:10:37: error: 'abs' was not declared in this scope
   if(x[j] == x[k] || abs(x[j] - x[k]) == abs(j - k))
                                     ^
0_0_37008771_24494.cpp: In function 'void BackTrace(int)':
0_0_37008771_24494.cpp:28:4: error: 'sum' was not declared in this scope
    sum++; 
    ^
0_0_37008771_24494.cpp: In function 'int main()':
0_0_37008771_24494.cpp:44:16: error: 'scanf' was not declared in this scope
   scanf("%d",&n);
                ^
0_0_37008771_24494.cpp:46:3: error: 'sum' was not declared in this scope
   sum = 0;
   ^
0_0_37008771_24494.cpp:49:20: error: 'printf' was not declared in this scope
   printf("%d\n",sum);
                    ^