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 <string>
#include <cmath>
using namespace std;

#define rep(i,n) for (int i = 0; i < int(n); i++)
typedef long long ll;

int it, n;
string input;

ll expr();
ll term();
ll fact();

ll expr() {
    int v = term();
    while (input[it] == '+' || input[it] == '-') {
        if (input[it++] == '+') {
            v += term();
        } else {
            v -= term();
        }
    }
    return v;
}

ll term() {
    int v = fact();
    while (input[it] == '*' || input[it] == '/') {
        if (input[it++] == '*') {
            v *= term();
        } else {
            v = (int)trunc(1.0*v/term());
            //v /= term();
        }
    }
    return v;
}

ll fact() {
    int v = 0;
    if (input[it] == '(') {
        ++it; // '('
        v = expr();
        ++it; // ')'
    } else {
        while ('0' <= input[it] && input[it] <= '9') {
            v = 10*v + input[it]-'0';
            ++it;
        }
    }
    return v;
}

int main() {
    cin >> n;
    rep (i,n) {
        cin >> input;
        it = 0;
        cout << expr() << endl;
    }
}

C++: #include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
#define INF (1<<24)

bool isNum(char ch){return ('0'<=ch&&ch<='9');}

struct calcStr{
  string s;
  int pos,len;
  bool flag;
  void init(){ pos=0;len=s.size(); flag=false; }

  int head2Num(){
    bool f=false;
    if(s[pos]=='-'){f=true;pos++;}
    int res=0;
    while(pos<len){
      if(isNum(s[pos])){
	res*=10;
	res+=(s[pos]-'0');
	pos++;
      }else break;
    }
    if(f)res*=-1;
    return res;
  }
  
  int getNum(){
    if(s[pos]=='('){
      pos++;
      return getAns();
    }
    int res=head2Num();
    if(s[pos]=='*'){
      pos++;
      return res*getNum();
    }else if(s[pos]=='/'){
      pos++;
      return res/getNum();
    }else{
      return res;
    }
  }
  
  int getAns(){
    int res=getNum(),num;
    while(1){
      if(s[pos]==')'){pos++;break;}
      if(s[pos]=='=')break;
      char ch=s[pos++];
      num=getNum();
      if(ch=='+')res+=num;
      else if(ch=='-')res-=num;
    }
    return res;
  }
};

int main(){
  int Tc;cin>>Tc;
  calcStr a;
  while(Tc--){
    cin>>a.s;
    a.init();
    cout<<a.getAns()<<endl;
  }
  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i,n) for( int i = 0; i < n; i++ )
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define INF 2000000000
#define mod 1000000007
#define INF2 1000000000000000000

int mul10 (int x, int y) {
    int ret = 1;
    for (int i = 0; i < x; i++) {
        ret *= 10;
    }
    ret *= y;
    return ret;
}

int cal (char sym, int x, int y) {
    if (sym == '+') {
        return x + y;
    } else if (sym == '*') {
        return x * y;
    } else if (sym == '-') {
        return x - y;
    } else if (sym == '/') {
        return x / y;
    }
}
int depth_parentheses (string str) {
    int count = 0;
    int count_max = 0;
    rep(i, str.length()) {
        if (str[i] == '(') count++;
        else if (str[i] == ')') count--;
        count_max = max(count_max, count);
    }
    return count_max;
}

int findL_parentheses (string str, int depth) {
    int L = 0;
    rep(i, str.length()) {
        if (str[i] == '(') L++;
        else if (str[i] == ')') L--;
        if (L == depth) {
            return i;
        }
    }
}

int findL_parentheses (string str) {
    int L = 0;
    int depth = depth_parentheses(str);
    rep(i, str.length()) {
        if (str[i] == '(') L++;
        else if (str[i] == ')') L--;
        if (L == depth) {
            return i;
        }
    }
}

int findR_parentheses (string str) {
    int R;
    int L = findL_parentheses(str);
    for (int i = L+1; i < str.length(); i++) {
        R = i;
        if (str[i] == ')') break;
    }
    return R;
}

int findR_parentheses (string str, int L) {
    int R;
    if (L == 0) L = findL_parentheses(str);
    for (int i = L+1; i < str.length(); i++) {
        R = i;
        if (str[i] == ')') break;
    }
    return R;
}
string takeout_parentheses (string str) {
    string ret;
    int depth = depth_parentheses(str);
    int L = findL_parentheses(str, depth);
    int R = findR_parentheses(str, L);
    //dump(depth);
    //dump(L);
    //dump(R);
    stringstream str_tmp;
    for (int i = L+1; i < R; i++) str_tmp << str[i];
    ret = str_tmp.str();
    return ret;
}

int find_muldiv (string str) {
    int sym = 0;
    while (str[sym] >= '0' && str[sym] <= '9' || str[sym] == '+' || str[sym] == '-') sym++;
    return sym;
}
int find_addsub (string str) {
    int sym = 0;
    while (str[sym] >= '0' && str[sym] <= '9') sym++;
    return sym;
}

string cal_mul (string str, int sym) {
    if (sym == str.length()) return str;

    int L = 1, R = 1;
    int sumL = 0, sumR = 0;
    while (str[sym-L] >= '0' && str[sym-L] <= '9') {
        sumL += mul10(L-1, (str[sym-L] - '0'));
        L++;
    }
    while (str[sym+R] >= '0' && str[sym+R] <= '9') {
        R++;
    }
    rep(i ,R-1) {
        sumR += mul10(i, str[sym+R-i-1] - '0');
    }
    //cout << sumL << endl;
    //cout << sumR << endl;
    stringstream str_tmp;
    rep(i, sym-L+1) str_tmp << str[i];
    str_tmp << cal(str[sym], sumL, sumR);
    for(int i = sym+R; i < str.length(); i++) str_tmp << str[i];
    str = str_tmp.str();
    //cout << str << endl;
    return str;
}

string cal_all (string str) {
    string prev = str;
    while(true){
        str = cal_mul(str, find_muldiv(str));
        if ( prev == str ) break;
        else prev = str;
    }
    while(true){
        str = cal_mul(str, find_addsub(str));
        if ( prev == str ) break;
        else prev = str;
    }
    return str;
}

int main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);

    int n; cin >> n;
    rep(i ,n){
        string str; cin >> str;
        str.erase( --str.end() );

        //?????£?????????????¨??????????
        while(depth_parentheses(str) > 0){
            string sube = takeout_parentheses(str);
            sube = cal_all(sube);

            int L = findL_parentheses(str);
            int R = findR_parentheses(str);
            stringstream str_tmp;
            rep(i, L) str_tmp << str[i];
            str_tmp << sube;
            for (int i = R+1; i < str.length(); i++) {
                str_tmp << str[i];
            }
            str = str_tmp.str();
            //cout << str << endl;
        }

        //?????£?????????????????¶?????§?¨??????????
        string prev = str;
        while(true){
            str = cal_mul(str, find_muldiv(str));
            if ( prev == str ) break;
            else prev = str;
        }
        while(true){
            str = cal_mul(str, find_addsub(str));
            if ( prev == str ) break;
            else prev = str;
        }
        //?????????????????????
        cout << str << endl;
    }
    return 0;
}