Language: C++

#include <bits/stdc++.h>
using namespace std;
// types
typedef long long ll; 
typedef unsigned long long ull;
typedef vector<int> vi;
typedef pair<int, int> pii;
// IO
#define fo(i, n) for (int i = 0; i < n; i++)
#define fo1(i, n) for (int i = 1; i <= n; i++)
#define sc(n) scanf("%d", &n) 
#define sca(a, n) fo(i, n) sc(a[i])
#define pd(a) printf("%d ", a)
#define pld(a) printf("%d\n", a)
#define pda(a, n) fo(i, n) pd(a[i])
#define pl printf("\n")
#define pb(a) push_back(a)
#define mp(a, b) make_pair(a, b) 
void Yes() {printf("Yes\n");}
void No() {printf("No\n");}
// math
const ll mod = 1e9+7;
template<typename T> T gcf(T a, T b) {return (b == 0) ? a : gcf(b, a%b);} 
template<typename T> T lcm(T a, T b) {return (a*b)/gcf(a, b);}
template<typename T> T sumTo(T x) {return x * (x+1) / 2;}
template<typename T> T sumSquaresTo(T x) {return x * (x+1) * (2*x+1) / 6;}
template<typename T> T ceilDiv(T n, T d) {return (n+d-1)/d;}

void solve() {
    string s; int k; cin >> s >> k;
    fo(i, min(s.size(), k)) cout << s[i];
    if (s.size() > k) cout << "...";
}

int main() {
    int t = 1;
    //scanf("%d", &t);
    while (t--) {
        solve();
    }
    return 0;
}

Compiler output:
a.cc: In function 'void solve()':
a.cc:31:14: error: no matching function for call to 'min(std::__cxx11::basic_string<char>::size_type, int&)'
   31 |     fo(i, min(s.size(), k)) cout << s[i];
      |           ~~~^~~~~~~~~~~~~
a.cc:9:38: note: in definition of macro 'fo'
    9 | #define fo(i, n) for (int i = 0; i < n; i++)
      |                                      ^
In file included from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_algobase.h:233:5: note: candidate: 'template<class _Tp> constexpr const _Tp& std::min(const _Tp&, const _Tp&)'
  233 |     min(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:233:5: note:   template argument deduction/substitution failed:
a.cc:31:14: note:   deduced conflicting types for parameter 'const _Tp' ('long unsigned int' and 'int')
   31 |     fo(i, min(s.size(), k)) cout << s[i];
      |           ~~~^~~~~~~~~~~~~
a.cc:9:38: note: in definition of macro 'fo'
    9 | #define fo(i, n) for (int i = 0; i < n; i++)
      |                                      ^
/usr/include/c++/14/bits/stl_algobase.h:281:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::min(const _Tp&, const _Tp&, _Compare)'
  281 |     min(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:281:5: note:   candidate expects 3 arguments, 2 provided
In file included from /usr/include/c++/14/algorithm:61:
/usr/include/c++/14/bits/stl_algo.h:5686:5: note: candidate: 'template<class _Tp> constexpr _Tp std::min(initializer_list<_Tp>)'
 5686 |     min(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5686:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5696:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::min(initializer_list<_Tp>, _Compare)'
 5696 |     min(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5696:5: note:   template argument deduction/substitution failed:
a.cc:31:14: note:   mismatched types 'std::initializer_list<_Tp>' and 'long unsigned int'
   31 |     fo(i, min(s.size(), k)) cout << s[i];
      |           ~~~^~~~~~~~~~~~~
a.cc:9:38: note: in definition of macro 'fo'
    9 | #define fo(i, n) for (int i = 0; i < n; i++)
      |                                      ^