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 <bits/stdc++.h>
using namespace std;
typedef string::const_iterator State;
class ParseError {};

struct Parser {
    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);
		    begin++;
            return ret;
	    } else {
		    return number(begin);
	    }
    }

    int term(State &begin) {
	    int ret = factor(begin);
	    while(1) {
	    	if(*begin == '*') {
	    		begin++;
	    		ret *= factor(begin);
	    	} else if(*begin == '/') {
                begin++;
	    		ret /= factor(begin);
	    	} else {
	    		break;
	    	}
    	}
    	return ret;
    }

    int expression(State &begin) {
	    int ret = term(begin);
	    while(1) {
	    	if(*begin == '+') {
		    	begin++;
		    	ret += term(begin);
	    	} else if(*begin == '-') {
	    		begin++;
		    	ret -= term(begin);
	    	} else {
	    		break;
	    	}
    	}
    	return ret;
    }
};

int main() {
    int N;
    cin >> N;
    for(int i = 0; i < N; i++) {
        Parser ps;
        string s;
        cin >> s;
        State begin = s.begin();
        int ans = ps.expression(begin);
        cout << ans << endl;
    }
    return 0;
}

C++: #include <iostream>
#include <string>
#include <cctype>
#include <vector>
#include <stdexcept>
using namespace std;
string input;

inline bool is_all_digit(string &in)
{
	for (auto i : in)
	{
		if (!isdigit(i))
			return false;
	}
	return true;
}
vector<string> split(string in)
{
	vector<string> spl;
	int pos = 0;
	if (in[pos] == '-') 
	{
		pos++;
		while (pos < in.size()) {
			if (isdigit(in[pos])) {
				pos++;
			}
			else {
				break;
			}
		}
		spl.push_back(in.substr(0, pos));
		in.erase(0, pos);
		pos = 0;
	}
	while ( pos < in.size())
	{
		if (!isdigit(in[pos]))
		{
			if (pos != 0)
			{
				spl.push_back(in.substr(0, pos));
				in.erase(0, pos);
				pos = 0;
			}
			else
			{
				if (in[0] == '(')
				{
					int cnt = 1;
					int r_pos = 1;
					for (r_pos = 1; r_pos < in.size(); r_pos++)
					{
						if (in[r_pos] == '(')
							cnt++;
						if (in[r_pos] == ')')
							cnt--;
						if (cnt == 0)
							break;
					}
					spl.push_back(in.substr(pos + 1, r_pos - 0 - 1));
					in.erase(0, r_pos + 1);
					pos = 0;
					continue;
				}
				else if (in[0] == '+' || in[0] == '-' || in[0] == '*' || in[0] == '/')
				{
					spl.push_back(in.substr(0, 1));
					in.erase(0, 1);
					pos = 0;
				}
			}
		}
		else {
			pos++;
		}
	}
	if (in.size() != 0) spl.push_back(in);
	return spl;
}
int cal(string &in_str) {
	auto in = split(in_str);
	while (in.size() == 1 && !is_all_digit(in[0])) {
		in = split(in[0]);
	}
	while (in.size() != 1) {
		auto pos = in.begin();
		while (pos != in.end()) 
		{
			if (*pos == "*") {
				pos--;
				*pos = to_string(cal(*pos)*cal(*(pos + 2)));
				in.erase(pos+1 , pos + 3);
			}
			else if (*pos == "/") {
				pos--;
				*pos = to_string(cal(*pos)/cal(*(pos + 2)));
				in.erase(pos+1, pos + 3);
			}
			if (in.size()==1) break;
			if (pos != in.end()) pos++;
		}
		pos = in.begin();
		while (pos != in.end()) {
			if (*pos == "+") {
				pos--;
				*pos = to_string(cal(*pos)+cal(*(pos + 2)));
				in.erase(pos+1, pos + 3);
			}
			else if (*pos == "-") {
				pos--;
				*pos = to_string(cal(*pos) - cal(*(pos + 2)));
				in.erase(pos+1, pos + 3);
			}
			if (in.size()==1) break;
			if(pos != in.end()) pos++;
		}
	}
	try {
		return(stoi(in[0]));
	}
	catch (const std::invalid_argument& a) {
		cerr << a.what() << input << endl;
	}
}
int main()
{
	
	int n;
	cin >> n;
	while (n--) {
		cin >> input;
		//input.erase(input.end() - 1);
		//cout << cal(input) << endl;
		cerr << input << endl;
	}

	return 0;
}

C++: 
#include <iostream>
#include <string>
#include <queue>
#include <vector>
#include <cctype>
using namespace std;

typedef string::const_iterator State;
int expression(State &begin);

typedef string::const_iterator State;
int expression(State &begin);

int number(State &begin) {
	int ret = 0;
	for (; isdigit(*begin);) {
		ret *= 10;
		ret += *begin - '0';
		begin++;
	}
	return ret;
}
int factor(State &begin) {
	int ret;
	if (*begin == '(') {
		begin++;
		ret = expression(begin);
		begin++;
	}
	else {
		return number(begin);
	}
	return ret;
}
int term(State &begin) {
	int ret = factor(begin);
	for (;;) {
		if (*begin == '*') {
			begin++;
			ret *= term(begin);
		}
		else if (*begin == '/') {
			begin++;
			ret /= term(begin);
		}
		else break;
	}
	return ret;
}


int expression(State &begin) {
	int ret = term(begin);
	for (;;) {
		if (*begin == '+') {
			begin++;
			ret += term(begin);
		}
		else if (*begin == '-') {
			begin++;
			ret -= term(begin);
		}
		else break;
	}
	return ret;
}

int main() {
	int N;
	cin >> N;
	cin.ignore();
	for (int i = 0; i < N; i++) {
		string str;
		getline(cin, str);
		State s = str.begin();
		cout << expression(s) << endl;
	}
	return 0;
}