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++: #define TEST_MODE true

#define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES

#include "bits/stdc++.h"
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(i, a, b) for (int i = (a); i < (b); ++i)
#define rrep(i, n) for (int i = (n)-1; i >= 0; --i)
#define rrep2(i, a, b) for (int i = (a)-1; i >= b; --i)
#define range(i, a, b, c) for (int i = a;             \
                               c > 0 ? i < b : i > b; \
                               i += c)
#define chmax(a, b) (a = (a) < (b) ? (b) : (a))
#define chmin(a, b) (a = (a) > (b) ? (b) : (a))
using ll = long long;
using ull = unsigned long long;
using ld = long double;
#define all(a) begin(a), end(a)
#define ifnot(a) if (not(a))
#define int long long

#ifdef LOCAL_ENV

#if TEST_MODE == true
const bool test = true;
#define dump(x) cerr << #x << " = " << (x) << endl
#else
const bool test = false;
#define dump(x) 
#endif

#else
const bool test = false;
#define dump(x) 
#endif

int dx[] = {1, 0, -1, 0};
int dy[] = {0, 1, 0, -1};
const int INF = (int)1 << 60;
const ll INFL = (ll)1 << 60;
ll mod_n = (int)1e9 + 7;
const double eps = 1e-10;
typedef long double Real;
// return -1, 0, 1
int sgn(const Real &r) { return (r > eps) - (r < -eps); }
int sgn(const Real &a, const Real &b) { return sgn(a - b); }

//.....................
const int MAX = (int)2e5 + 5;

vector<string> split(const string &str, char sep)
{
    vector<string> v;
    stringstream ss(str);
    string buffer;
    while (getline(ss, buffer, sep))
    {
        v.push_back(buffer);
    }
    return v;
}

template <class InputIterator>
int sum(InputIterator begin, InputIterator end)
{
    return accumulate(begin, end, 0ll);
}

void solve();

signed main()
{
    cout << fixed << setprecision(20);
    solve();
    return 0;
}

// class Mycin {
// 	bool flag = true;
// public:
// 	Mycin& operator >> (int& a) {flag = scanf("%lld", &a) != EOF; return *this;}
// 	Mycin& operator >> (char& a) {flag = scanf("%c", &a) != EOF; return *this;}
// 	Mycin& operator >> (string& s) {flag = (bool)(cin >> s); return *this;}
// 	operator bool() {return flag;}
// } mycin;
 
// class Mycout {
// public:
// 	Mycout& operator << (const int& a) {printf("%lld", a); return *this;}
// 	Mycout& operator << (const char c) {printf("%c", c); return *this;}
// 	Mycout& operator << (const string& s) {printf("%s", s.c_str()); return *this;}
// } mycout;
 
// #define cin mycin
// #define cout mycout
// #define endl '\n'

int number(const string& s, int& i);
int factor(const string& s, int& i);
int term(const string& s, int& i);
int expr(const string& s, int& i);

int number(const string& s, int& i) {
    int res = 0;
    bool minus_flag = false;
    if (s[i] == '-') {
        minus_flag = true;
        i++;
    }
    for (; isdigit(s[i]); i++) {
        res *= 10;
        res += s[i] - '0';
    }
    if (minus_flag) res *= -1;
    return res;
}

int factor(const string& s, int& i) {
    if (isdigit(s[i]) || s[i] == '-') return number(s, i);
    i++;
    int res = expr(s, i);
    i++;
    return res;
}

int term(const string& s, int& i) {
    int res = factor(s, i);
    while (s[i] == '*' || s[i] == '/') {
        char op = s[i];
        i++;
        int a = factor(s, i);
        if (op == '*') res *= a;
        else           res /= a;
    }
    return res;
}

int expr(const string& s, int& i) {
    int res = term(s, i);
    while (s[i] == '+' || s[i] == '-') {
        char op = s[i];
        i++;
        int a = term(s, i);
        if (op == '+') res += a;
        else           res -= a;
    }
    return res;
}

int eval(const string& s) {
    int i = 0;
    return expr(s, i);
}

void solve() {
    int N;
    string s;
    cin >> N;
    rep(i, N) {
        cin >> s;
        cout << eval(s) << endl;
    }
}

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

//const string S = "1+2+3";
//const string S = "1*5+2+3";
/*const*/ string S;
size_t cur = 0; //解析開始位置

int digit() {
  assert(isdigit(S[cur])); //S[cur]が数字であることの確認
  int n = S[cur] - '0'; //'0'を0に変換
  cur = cur + 1;
  return n;
  }
  
int number() {
  int n = digit();
  while (cur < S.size() && isdigit(S[cur])) //次も数字か1文字先読
   n = n*10 + digit();
  return n;
  }
  
int term() {
  int a = number();
  while (cur < S.size()
    && (S[cur] == '*' || S[cur] == '/')) {
	  char op = S[cur++];
	  int b = number();
	  if (op == '*') a *= b; else a /= b;
	  }
  return a;
  }
  
int expression() {
  int a = term();
  while ((cur < S.size())&&(S[cur] == '+' || S[cur] == '-')) {
    char op = S[cur++];
	int b = term();
	if (op == '+'){
      a += b;
	 }
	else{
	  a -= b;
	  }
	}
  return a;
  }
  
int ezpression(); //前方宣言

int factor() {
  if (S[cur] != '(') return number();
  cur += 1;
  int n = expression();
  assert(S[cur] == ')');
  cur += 1;
  return n;
  }

int parse() {return expression(); }

int main() {
   int N;
   cin >> N;
   for (int i=0; i<N; ++i){
     cur = 0;
	 cin >> S;
	 S.resize(S.size()-1); //最後の=属性を無視
	 cout << expression() << endl;
  }
 }
  
/*

 コンパイルは通るが、
Assertion failed: (isdigit(S[cur])), function digit, file 12-1-1-1.cc, line 10.
Abort trap: 6
と表示されてうまくいかない。
どうしてでしょうか?

*/

C++: #include <cassert>
#include <cctype>
#include <vector>
#include <string>
#include <iostream>
#include <algorithm>

using namespace std;
string S = "";
int cur;
int digit(){
	assert(isdigit(S[cur]));
	int n = S[cur] - '0';
	cur = cur+1;
	return n;
}
int number(){
	int n = digit();
	while(cur < S.size() && isdigit(S[cur]))
		n = n*10 + digit();
	return n;
}
int factor();

int term(){
	int a = factor();
	while(cur < S.size() && (S[cur] == '*' || S[cur] == '/')){
		char op = S[cur++];
		int b = factor();
		if(op == '*'){
			a *= b;
		}else{
			a /= b;
		}
	}
	return a;
}

int expression(){
	int sum = term();
	while (cur < S.size() && (S[cur] == '+' || S[cur] == '-')){
		char op = S[cur];
		cur++;
		int b = term();
		if(op == '+'){
			sum += b;
		}else{
			sum -= b;
		}
	}
	return sum;
}

int factor(){
	if(S[cur] != '('){
		return number();
	}
	cur += 1;
	int n = expression();
	assert(S[cur] == ')');
	cur += 1;
	return n;
}

int main(){
	int N;
	cin >> N;
	for(int i = 0;i<N;i++){
		cur = 0;
		cin >> S;
		S.erase(S.size()-1);
		cout << expression() << endl;
	}
}