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;

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

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

int factor(State &begin) {
  int ret = 0;
  if (*begin == '(') {
    begin++;
    ret = expression(begin);
    begin++;
    return ret;
  } else {
    ret = number(begin);
  }
  return ret;
}

int number(State &begin) {
  int ret = 0;
  while (isdigit(*begin)) {
    ret *= 10;
    ret += *begin - '0';
    begin++;
  }
  return ret;
}

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

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

//????¨???????????¶????????????¨???????????????
class CAL{
private:
  string m_str;
  size_t m_cur;
  int digit();
  int number();
  int term();
  int expression();
  int factor();
  int calterm();
public:
  CAL(string str);
  int cal();
};

//?????????????????????
CAL::CAL(string str)
{
  m_str = str;
  m_cur = 0;
  m_str.resize(m_str.size() - 1);
}

//??????????????°????????°????????????
int CAL::digit()
{
  assert(isdigit(m_str[m_cur]));
  int n = m_str[m_cur++] - '0';
  return n;
}

//??°??????????????¨?????¨???????????°??????????????????
int CAL::number()
{
  int n = digit();
  while(m_cur < m_str.size() && isdigit(m_str[m_cur]))
    n = n*10 + digit();
  return n;
}

//???????????¨?????????????°???\
int CAL::term()
{
  int a = number();
  while(m_cur < m_str.size() && (m_str[m_cur] == '*' || m_str[m_cur] == '/')){
    char op = m_str[m_cur++];
    int b = number();
    if(op == '*') a *= b; else if(op == '/') a /= b;
  }
  return a;
}

//??¬??§???????????????????????????
int CAL::expression()
{
  int a = term();
  while(m_cur < m_str.size() && (m_str[m_cur] == '+' || m_str[m_cur] == '-')){
    char op = m_str[m_cur++];
    int b = term();
    if(op == '+') a += b; else if(op == '-') a -= b;
  }
  return a;
}

//??¬??§???????????????????????°?????¨?????????????????????number()??????????????????
int CAL::factor()
{
  if(m_str[m_cur] != '(') return number();
  m_cur += 1;
  int n = expression();
  assert(m_str[m_cur] == ')');
  m_cur += 1;
  return n;
}

//??¬??§????????£?????´?????????????????¨?????????????°???\
int CAL::calterm()
{
  int a = factor();
  while(m_cur < m_str.size() && (m_str[m_cur] == '*' || m_str[m_cur] == '/')){
    char op = m_str[m_cur++];
    int b = factor();
    if(op == '*') a *= b; else if(op == '/') a /= b;
  }
  return a;
}

//??¬??§????????£?????´???????????????????????????????¨????
int CAL::cal()
{
  int a = calterm();
  while(m_cur < m_str.size() && (m_str[m_cur] == '+' || m_str[m_cur] == '-')){
    char op = m_str[m_cur++];
    int b = calterm();
    if(op == '+') a += b; else if(op == '-') a -= b;
  }
  return a;
}

int main()
{
  int N;
  cin >> N;
  queue<int> answer;
  string str;
  for(int i = 0; i < N; ++i){
    cin >> str;
    CAL a(str);
    answer.push(a.cal());
  }
  while(!answer.empty()){
    cout << answer.front() << endl;
    answer.pop();
  }
}

C++:             #include <bits/stdc++.h>
            #include<iostream>
            #include<cstdio>
            #include<vector>
            #include<queue>
            #include<map>
            #include<cstring>
            #include<string>
            #include <math.h>
            #include<algorithm>
        //    #include <boost/multiprecision/cpp_int.hpp>
            #include<functional>
  //   #define int long long
            #define mod  1000000009
            #define pa pair<int,int>
            #define ll long long
            #define pal pair<double,int>
            #define ppa pair<int,pa>
            #define ssa pair<string,int>
            #define  mp make_pair
            #define  pb push_back
            #define EPS (1e-10)
            #define equals(a,b) (fabs((a)-(b))<EPS)
     
            using namespace std;
     //priority_queue<int, vector<int>, greater<int> > que;
            class Point{
            	public:
            	double x,y;
            	Point(double x=0,double y=0):x(x),y(y) {}
            	Point operator + (Point p) {return Point(x+p.x,y+p.y);}
            	Point operator - (Point p) {return Point(x-p.x,y-p.y);}
            	Point operator * (double a) {return Point(x*a,y*a);}
            	Point operator / (double a) {return Point(x/a,y/a);}
            	double absv() {return sqrt(norm());}
            	double norm() {return x*x+y*y;}
            	bool operator < (const Point &p) const{
            		return x != p.x ? x<p.x: y<p.y;
            	}
            	bool operator == (const Point &p) const{
            		return fabs(x-p.x)<EPS && fabs(y-p.y)<EPS;
            	}
            };
            typedef Point Vector;
     
            struct Segment{
            Point p1,p2;
            };
     
        double hen(Vector a){
        if(fabs(a.x)<EPS && a.y>0) return acos(0);
        else if(fabs(a.x)<EPS && a.y<0) return 3*acos(0);
        else if(fabs(a.y)<EPS && a.x<0) return 2*acos(0);
        else if(fabs(a.y)<EPS && a.x>0) return 0.0;
        else if(a.y>0) return acos(a.x/a.absv());
        else return 2*acos(0)+acos(-a.x/a.absv());
     
        }
     
string itos( int i ) {
ostringstream s ;
s << i ;
return s.str() ;
}

int gcd(int v,int b){
	if(v>b) return gcd(b,v);
	if(v==b) return b;
	if(b%v==0) return v;
	return gcd(v,b%v);
}
            double dot(Vector a,Vector b){
            	return a.x*b.x+a.y*b.y;
            }
            double cross(Vector a,Vector b){
            	return a.x*b.y-a.y*b.x;
            }
        
double distans(double x1,double y1,double x2,double y2){
	double rr=(x1-x2)*(x1-x2)+(y1-y2)*(y1-y2);
	return sqrt(rr);
	
}
            //----------------kokomade tenpure------------
string s;
int kakko(string &t ,int &b);

int suuji(string &t, int &b){
	int r=0;
	if(isdigit(t[b])){
	while(isdigit(t[b])){
		r *=10;
		r += t[b]-'0';
		(b)++;
	}
	}
	else if(t[b]=='('){
	
		r=kakko(t,b);
		
	}
	
	return r;
}


int kake(string &t, int &b){
	if(isdigit(t[b])||t[b]=='('){
		int i=suuji(t,b);
	
		while((t[b]=='*')||(t[b]=='*')){
			b++;
			if(t[b-1]=='*')i *= suuji(t,b);
			else i /= suuji(t,b);
		}
		return i;
	}
}

int tashi(string &t ,int &b){
	if(isdigit(t[b])||t[b]=='('){
		int i=kake(t,b);
		while((t[b]=='+')||(t[b]=='-')){
		b++;
			if(t[b-1]=='+')	i += kake(t,b);
			else i -= kake(t,b);
		}
		return i;
	}
}

int kakko(string &t ,int &b){
	
	if(t[b]=='('){
		int y;
		b++;
		y=kakko(t,b);
		b++;
		return y;
	}
	else{
		return tashi(t,b);
	}
}
    signed  main(){
    	int n;
    	cin>>n;
    	for(int g=0;g<n;g++){
cin>>s;
    	int i=0;
    	cout<<tashi(s,i)<<endl;
    	}
    
  //  	printf("%.10f\n",ans[n-1]);
    	return 0;
    }