Language: C++

#include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (n); i++)
#define rep1(i,n) for (int i = 1; i <= (n); i++)
#define for(i,a,b) for (int i = (a); i < (b); i++)
#define repi(i,a,b) for (int i = (a); i <= (b); i++)
#define all(x) (x).begin(),(x).end()
using namespace std;
using uint = unsigned int;
using ll = long long;
using ull = unsigned long long;
using vi = vector<int>;
using vvi = vector<vi>;
using pii = pair<int, int>;
using vc = vector<char>;
using vvc = vector<vc>;
using vs = vector<string>;
using tiii = tuple<int, int, int>;

int main() {
  int N; cin >> N;
  vi V(N); rep(i,N) cin >> V.at(i);
  vi C(N); rep(i,N) cin >> C.at(i);
  
  int ans = 0;
  rep(i,N) {
    if (V.at(i) > C.at(i)) {
      ans += V.at(i) - C.at(i);
    }
  }
  
  cout << ans << endl;
}

Compiler output:
a.cc:21:19: error: macro "for" requires 3 arguments, but only 1 given
   21 |   vi V(N); rep(i,N) cin >> V.at(i);
      |                   ^
a.cc:4:9: note: macro "for" defined here
    4 | #define for(i,a,b) for (int i = (a); i < (b); i++)
      |         ^~~
a.cc:22:19: error: macro "for" requires 3 arguments, but only 1 given
   22 |   vi C(N); rep(i,N) cin >> C.at(i);
      |                   ^
a.cc:4:9: note: macro "for" defined here
    4 | #define for(i,a,b) for (int i = (a); i < (b); i++)
      |         ^~~
a.cc:25:10: error: macro "for" requires 3 arguments, but only 1 given
   25 |   rep(i,N) {
      |          ^
a.cc:4:9: note: macro "for" defined here
    4 | #define for(i,a,b) for (int i = (a); i < (b); i++)
      |         ^~~
a.cc: In function 'int main()':
a.cc:21:21: error: expected '(' before 'cin'
   21 |   vi V(N); rep(i,N) cin >> V.at(i);
      |                     ^~~
      |                     (
a.cc:21:33: error: 'i' was not declared in this scope
   21 |   vi V(N); rep(i,N) cin >> V.at(i);
      |                                 ^
a.cc:22:7: error: expected initializer before '(' token
   22 |   vi C(N); rep(i,N) cin >> C.at(i);
      |       ^
a.cc:22:7: error: could not convert 'C' from 'vi' {aka 'std::vector<int>'} to 'bool'
   22 |   vi C(N); rep(i,N) cin >> C.at(i);
      |       ^
      |       |
      |       vi {aka std::vector<int>}
a.cc:22:7: error: expected ';' before '(' token
   22 |   vi C(N); rep(i,N) cin >> C.at(i);
      |       ^
      |       ;
a.cc:22:10: error: expected ')' before ';' token
   22 |   vi C(N); rep(i,N) cin >> C.at(i);
      |          ^
      |          )
a.cc:21:21: note: to match this '('
   21 |   vi V(N); rep(i,N) cin >> V.at(i);
      |                     ^~~
a.cc:22:21: error: expected '(' before 'cin'
   22 |   vi C(N); rep(i,N) cin >> C.at(i);
      |                     ^~~
      |                     (
a.cc:22:28: error: 'C' was not declared in this scope
   22 |   vi C(N); rep(i,N) cin >> C.at(i);
      |                            ^
a.cc:22:33: error: 'i' was not declared in this scope
   22 |   vi C(N); rep(i,N) cin >> C.at(i);
      |                                 ^
a.cc:2:18: error: expected primary-expression before 'for'
    2 | #define rep(i,n) for (int i = 0; i < (n); i++)
      |                  ^~~
a.cc:25:3: note: in expansion of macro 'rep'
   25 |   rep(i,N) {
      |   ^~~
a.cc:24:15: error: expected ')' before 'for'
   24 |   int ans = 0;
      |               ^
      |               )
a.cc:22:21: note: to match this '('
   22 |   vi C(N); rep(i,N) cin >> C.at(i);
      |                     ^~~
a.cc:25:12: error: expected '(' before '{' token
   25 |   rep(i,N) {
      |            ^
      |            (
a.cc:25:12: error: expected primary-expression before '{' token
a.cc:32:1: error: expected primary-expression before '}' token
   32 | }
      | ^
a.cc:31:23: error: expected ')' before '}' token
   31 |   cout << ans << endl;
      |                       ^
      |                       )
   32 | }
      | ~                      
a.cc:25:12: note: to match this '('
   25 |   rep(i,N) {
      |            ^
a.cc:32:1: error: expected primary-expression before '}' token
   32 | }
      | ^