Go: package main

import (
	"bufio"
	"fmt"
	"go/token"
	"go/types"
	"os"
	"strconv"
	"strings"
)

func main() {
	stdin := bufio.NewScanner(os.Stdin)
	stdin.Scan()
	n, _ := strconv.Atoi(stdin.Text())
	for i := 0; i < n; i++ {
		stdin.Scan()
		exp := strings.TrimRight(stdin.Text(), "=")
		res, _ := types.Eval(token.NewFileSet(), nil, token.NoPos, exp)
		fmt.Println(res.Value)
	}
}

C++: #include <iostream>
#include <sstream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <ctime>
#include <cstring>
#include <string>
#include <vector>
#include <stack>
#include <queue>
#include <deque>
#include <map>
#include <set>
#include <bitset>
#include <numeric>
#include <utility>
#include <iomanip>
#include <algorithm>
#include <functional>
using namespace std;

typedef long long ll;
typedef vector<int> vint;
typedef vector<ll> vll;
typedef pair<int,int> pint;

#define DE 1
#define FI first
#define SE second
#define PB push_back
#define MP make_pair
#define ALL(s) (s).begin(),(s).end()
#define REP(i,n) for (int i = 0; i < (int)(n); ++i)
#define EACH(i,s) for (typeof((s).begin()) i = (s).begin(); i != (s).end(); ++i)
#define COUT(x) cout<<#x<<" = "<<(x)<<" (L"<<__LINE__<<")"<<endl

template<class T1, class T2> ostream& operator<<(ostream &s, pair<T1,T2> P){return s<<'<'<<P.first<<", "<<P.second<<'>';}
template<class T> ostream& operator<<(ostream &s, vector<T> P) {s<<"{ ";for(int i=0;i<P.size();++i){if(i>0)s<<", ";s<<P[i];}return s<<" }"<<endl;}
template<class T1, class T2> ostream& operator<<(ostream &s, map<T1,T2> P) {s<<"{ ";for(typeof(P.begin()) it=P.begin();it!=P.end();++it){if(it!=P.begin())s<<", ";s<<'<'<<it->first<<"->"<<it->second<<'>';}return s<<" }"<<endl;}



typedef pair<int,int> parsed;

parsed equation(string str, int p = 0);
parsed factor(string str, int p = 0);
parsed term(string str, int p = 0);

bool overflow = false;

int conv(string str) {
    int res = 0;
    for (int i = 0; i < str.size(); ++i) {
        res = res * 10 + (str[i] - '0');
    }
    return res;
}

parsed equation(string str, int p) {
    parsed res = factor(str, p);
    while (str[res.second] == '+' || str[res.second] == '-') {
        parsed temp = factor(str, res.second+1);
        if (str[res.second] == '+') res.first = res.first + temp.first;
        else if (str[res.second] == '-') res.first = res.first - temp.first;
        res.second = temp.second;
    }
    return res;
}

parsed factor(string str, int p) {
    parsed res = term(str, p);
    while (str[res.second] == '*' || str[res.second] == '/') {
        parsed temp = term(str, res.second+1);    
        if (str[res.second] == '*') res.first = res.first * temp.first;
        else if (str[res.second] == '/') res.first = res.first / temp.first;
        res.second = temp.second;
    }
    return res;
}

parsed term(string str, int p) {
    if (str[p] == '(') {
        parsed res = equation(str, p+1);
        res.second += 1;
        return res;
    }
    else {
        string snum = "";
        if (p < str.size()) {
            while (isdigit(str[p]) || str[p] == 'i') {
                snum += str[p++];
            }
        }
        int num = conv(snum);
        return parsed(num, p);
    }
}


int main() {
    //freopen( "/Users/macuser/Documents/Programming/Contest/input.in", "r", stdin );
    
    int n;
    cin >> n;
    string str;
    for (int i = 0; i < n; ++i) {
        cin >> str;
        cout << equation(str).FI << endl;
    }
    
    return 0;
}

C++: #include <string>
#include <cctype>
#include <iostream>
typedef std::string::iterator State;
using namespace std;

 
int number(State &begin);
int factor(State &begin);
int expression(State &begin);

int main(void){
  int N;
  std::cin >> N;

  while(N--){
    std::string s;
    std::cin>>s;
    State begin = s.begin();
    int ans = expression(begin);
    std::cout << ans << std::endl;
  }
  return 0;
}
 
int number(State &begin){
  int ret = 0;
 
  while(isdigit(*begin)){
    ret *= 10;
    ret += *begin - '0';
    begin++;
  }
 
  return ret;
}
 
int factor(State &begin){
  if(*begin == '('){
    begin++;
    int ret = expression(begin);
    return ret;
  }else{
    return number(begin);
  }
}
 

 
int expression(State &begin){
  int num = factor(begin);
  int sum = 0;
  
  for(;;){
    char ch = *begin;
    begin++;
    if(ch == '+'){
      num += factor(begin);
    } else if(ch == '-'){
      num -= factor(begin);
    }else if(ch == '*'){
      sum += num;
      num = factor(begin);
    }else if(ch == '/'){
      sum += num;
      num = factor(begin);
    }else{
      break;
    }
  }
  return sum+num;
}