Evaluate simple algebraic expression

#include<iostream>
#include<deque>
#include<cstdlib>
#include<cstring>
using namespace std;

int compute(deque<int> &numbers, deque<char> &operators) {
        char operation;
        int operand1, operand2, t;
        while(!operators.empty()) {
                operation = operators.front(); operators.pop_front();
                operand1 = numbers.front(); numbers.pop_front();
                operand2 = numbers.front(); numbers.pop_front();
                if(operation == '+') t = operand1 + operand2;
                else if(operation == '-') t = operand1 - operand2;
                else if(operation == '/') t = operand1 / operand2;
                else if(operation == '*') t = operand1 * operand2;
                numbers.push_front(t);
        }
        int result = numbers.front(); numbers.pop_front();
        return result;
}

void evaluate(char* exp) {
        deque<int> numbers, numbers_brackets;
        deque<char> operators, operators_brackets;
        char* token = strtok(exp, " ");
        while(token != NULL) {
                if(isdigit(token[0])) numbers.push_back(atoi(token));
                else if(token[0] == '+' || token[0] == '-' || token[0] == '/' || token[0] == '*') {
                        operators.push_back(token[0]);
                } else if(token[0] == '(') {
                        token = strtok(NULL, " ");
                        while(token != NULL && token[0] != ')') { //assuming input is valid w.r.t to brackets
                                if(isdigit(token[0])) numbers_brackets.push_back(atoi(token));
                                else if(token[0] == '+' || token[0] == '-' || token[0] == '/' || token[0] ==     '*') operators_brackets.push_back(token[0]);
                                token = strtok(NULL, " ");
                        }
                        numbers.push_back(compute(numbers_brackets, operators_brackets)); // Compute things within bracket and push_back the result to the original stack
                }
                token = strtok(NULL, " ");
        }
        cout << "Ans:" << compute(numbers,operators) << endl;
}

int main() {
        char input[100];
        scanf("%[^\n]s",input);
        evaluate(input);
}