Language: C++

#include<iostream>
#include<string>
#include<sstream>
using namespace std;

ll stol(string s){
  stringstream ss(s);
  ll n;
  ss >> n;
  return n;
}

ll parse(int l, int r){
  int n = 0,i;
  for(i=r-1;i>=l;i--){
    if(s[i] == ‘)‘)n++;  if(s[i] == ‘(’)n--;
    if(!n){
      if(s[i] == ‘+’)return parse(l,i)+parse(i+1,r);
      if(s[i] == ‘-’)return parse(l,i)-parse(i+1,r);
    }
  }
  for(i=r-1;i>=l;i--){
    if(s[i] == ‘)‘)n++;  if(s[i] == ‘(’)n--;
    if(!n){
      if(s[i] == ‘*’)return parse(l,i)*parse(i+1,r);
      if(s[i] == ‘/’)return parse(l,i)/parse(i+1,r);
    }
  }

  if(s[l] == ‘(‘ && s[r-1] == ‘)’)return parse(l+1,r-1);
  return stol(s.substr(l,r-l));
}

int main(){
  int n;
  string s;
  cin >> n;
  while(n--){
    cin >> s;
    cout << parse(0,(int)s.size()-1) << endl;
  }
}

Compiler output:
a.cc:16:16: error: extended character ‘ is not valid in an identifier
   16 |     if(s[i] == ‘)‘)n++;  if(s[i] == ‘(’)n--;
      |                ^
a.cc:16:18: error: extended character ‘ is not valid in an identifier
   16 |     if(s[i] == ‘)‘)n++;  if(s[i] == ‘(’)n--;
      |                  ^
a.cc:16:37: error: extended character ‘ is not valid in an identifier
   16 |     if(s[i] == ‘)‘)n++;  if(s[i] == ‘(’)n--;
      |                                     ^
a.cc:16:39: error: extended character ’ is not valid in an identifier
   16 |     if(s[i] == ‘)‘)n++;  if(s[i] == ‘(’)n--;
      |                                       ^
a.cc:18:18: error: extended character ‘ is not valid in an identifier
   18 |       if(s[i] == ‘+’)return parse(l,i)+parse(i+1,r);
      |                  ^
a.cc:18:20: error: extended character ’ is not valid in an identifier
   18 |       if(s[i] == ‘+’)return parse(l,i)+parse(i+1,r);
      |                    ^
a.cc:19:18: error: extended character ‘ is not valid in an identifier
   19 |       if(s[i] == ‘-’)return parse(l,i)-parse(i+1,r);
      |                  ^
a.cc:19:20: error: extended character ’ is not valid in an identifier
   19 |       if(s[i] == ‘-’)return parse(l,i)-parse(i+1,r);
      |                    ^
a.cc:23:16: error: extended character ‘ is not valid in an identifier
   23 |     if(s[i] == ‘)‘)n++;  if(s[i] == ‘(’)n--;
      |                ^
a.cc:23:18: error: extended character ‘ is not valid in an identifier
   23 |     if(s[i] == ‘)‘)n++;  if(s[i] == ‘(’)n--;
      |                  ^
a.cc:23:37: error: extended character ‘ is not valid in an identifier
   23 |     if(s[i] == ‘)‘)n++;  if(s[i] == ‘(’)n--;
      |                                     ^
a.cc:23:39: error: extended character ’ is not valid in an identifier
   23 |     if(s[i] == ‘)‘)n++;  if(s[i] == ‘(’)n--;
      |                                       ^
a.cc:25:18: error: extended character ‘ is not valid in an identifier
   25 |       if(s[i] == ‘*’)return parse(l,i)*parse(i+1,r);
      |                  ^
a.cc:25:20: error: extended character ’ is not valid in an identifier
   25 |       if(s[i] == ‘*’)return parse(l,i)*parse(i+1,r);
      |                    ^
a.cc:26:18: error: extended character ‘ is not valid in an identifier
   26 |       if(s[i] == ‘/’)return parse(l,i)/parse(i+1,r);
      |                  ^
a.cc:26:20: error: extended character ’ is not valid in an identifier
   26 |       if(s[i] == ‘/’)return parse(l,i)/parse(i+1,r);
      |                    ^
a.cc:30:14: error: extended character ‘ is not valid in an identifier
   30 |   if(s[l] == ‘(‘ && s[r-1] == ‘)’)return parse(l+1,r-1);
      |              ^
a.cc:30:16: error: extended character ‘ is not valid in an identifier
   30 |   if(s[l] == ‘(‘ && s[r-1] == ‘)’)return parse(l+1,r-1);
      |                ^
a.cc:30:31: error: extended character ‘ is not valid in an identifier
   30 |   if(s[l] == ‘(‘ && s[r-1] == ‘)’)return parse(l+1,r-1);
      |                               ^
a.cc:30:33: error: extended character ’ is not valid in an identifier
   30 |   if(s[l] == ‘(‘ && s[r-1] == ‘)’)return parse(l+1,r-1);
      |                                 ^
a.cc:6:1: error: 'll' does not name a type
    6 | ll stol(string s){
      | ^~
a.cc:13:1: error: 'll' does not name a type
   13 | ll parse(int l, int r){
      | ^~
a.cc: In function 'int main()':
a.cc:40:13: error: 'parse' was not declared in this scope
   40 |     cout << parse(0,(int)s.size()-1) << endl;
      |             ^~~~~