Language: C++

#include <bits/stdc++.h>
using namespace std;
struct cww{cww(){ios::sync_with_stdio(false);cin.tie(0);}}star;
#define P(x) cout << (x) << "\n"
#define p(x) cout << (x)
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define vv(type, c, m, n, i) vector<vector<type>> c(m, vector<type>(n, i));
#define rep(i,a,n) for(int i=(a), i##_len=(n); i<i##_len; ++i)
#define rrep(i,a,n) for(int i=(a), i##_len=(n); i>i##_len; --i)
#define len(x) ((int)(x).size())
#define mp make_pair
#define eb emplace_back
#define fi first
#define se second
#define chmax(a,b) if(a<b)a=b;
#define chmin(a,b) if(b<a)a=b;
typedef long long ll;
typedef long double ld;
typedef vector<int> vi;
typedef vector<double> vd;
typedef vector<long long> vll;
typedef vector<string> vs;
typedef vector<bool> vb;
typedef pair<int, int> pii;
#define N 8
#define FREE -1
#define NOT_FREE 1
vi row(N, FREE), col(N, FREE), dpos(2 * N - 1, FREE), dneg(2 * N - 1, FREE);
vv(bool, X, N, N, false);
	rep(i, 0, N) {
		rep(j, 0, N) {
			if(X[i][j] != 0 && row[i] != j) return;
		}
	}
	rep(i, 0, N) {
		rep(j, 0, N) {
			p((row[i] == j) ? "Q" : ".");
		}
		P("");
	}
}
void recursive(int i) {
	if(i == N) {
	}
	rep(j, 0, N) {
		if (NOT_FREE == col[j] ||
			NOT_FREE == dpos[i + j] ||
			NOT_FREE == dneg[i - j + N - 1]) continue;
		row[i] = j; col[j] = dpos[i + j] = dneg[i - j + N - 1] = NOT_FREE;
		recursive(i + 1);
		row[i] = col[j] = dpos[i + j] = dneg[i - j + N - 1] = FREE;
	}
}
int main() {
	int k; cin >> k;
	int r, c;
	rep(i, 0, k) {
		cin >> r >> c;
		X[r][c] = true;
	}
	recursive(0);
	return 0;
}

Compiler output:
a.cc:9:20: error: expected unqualified-id before 'for'
    9 | #define rep(i,a,n) for(int i=(a), i##_len=(n); i<i##_len; ++i)
      |                    ^~~
a.cc:31:9: note: in expansion of macro 'rep'
   31 |         rep(i, 0, N) {
      |         ^~~
a.cc:31:13: error: 'i' does not name a type; did you mean 'vi'?
   31 |         rep(i, 0, N) {
      |             ^
a.cc:9:48: note: in definition of macro 'rep'
    9 | #define rep(i,a,n) for(int i=(a), i##_len=(n); i<i##_len; ++i)
      |                                                ^
a.cc:9:59: error: expected unqualified-id before '++' token
    9 | #define rep(i,a,n) for(int i=(a), i##_len=(n); i<i##_len; ++i)
      |                                                           ^~
a.cc:31:9: note: in expansion of macro 'rep'
   31 |         rep(i, 0, N) {
      |         ^~~
a.cc:9:20: error: expected unqualified-id before 'for'
    9 | #define rep(i,a,n) for(int i=(a), i##_len=(n); i<i##_len; ++i)
      |                    ^~~
a.cc:36:9: note: in expansion of macro 'rep'
   36 |         rep(i, 0, N) {
      |         ^~~
a.cc:36:13: error: 'i' does not name a type; did you mean 'vi'?
   36 |         rep(i, 0, N) {
      |             ^
a.cc:9:48: note: in definition of macro 'rep'
    9 | #define rep(i,a,n) for(int i=(a), i##_len=(n); i<i##_len; ++i)
      |                                                ^
a.cc:9:59: error: expected unqualified-id before '++' token
    9 | #define rep(i,a,n) for(int i=(a), i##_len=(n); i<i##_len; ++i)
      |                                                           ^~
a.cc:36:9: note: in expansion of macro 'rep'
   36 |         rep(i, 0, N) {
      |         ^~~
a.cc:42:1: error: expected declaration before '}' token
   42 | }
      | ^