c++ - How can I resolve <could not resolve type> message on operator "=" for deque<int>? -

i have passed deque variable function reference , trying set equal local deque variable of same type.

in main define:

vector<vector<deque<int>>> memo_r (max_city, vector<deque<int>>((1<<(max_city))-1)); 

then in function:

double held_karp( ... , vector<vector<deque<int>>> &memo_r, ... ){   deque<int> temp_route;   temp_route.push_front(0);   memo_r[x][y] = temp_route; } 

but values temp_route not placed in memo_r[x][y]. when debugging message <could not resolve type>. why might be? steps can fix/debug problem?

thanks!

all related code:

double held_karp(int pos, long long unsigned city_bit, int max_city, const vector<vector<double>>&graph, vector<vector<double>> &memo, vector<vector<deque<int>>> &memo_r, deque<int> &deque_reference) {     if (city_bit == (1<<(max_city))-1) {         //printf("%d 1^\n",pos);         return graph[pos+1][0+1];     }      if (memo[pos][city_bit] != -1) {         //printf("%d 2^\n",pos);         return memo[pos][city_bit];     }      //ensure "lowest_result" accepted     double lowest_result = numeric_limits<double>::max();     deque<int> temp_route;     (int = 0; < max_city; i++) {         if (i != pos && (city_bit & (1 << i)) == 0){             deque<int> lower_deque_local;             //printf("%d !\n",pos);             double new_lower = graph[pos+1][i+1] + held_karp(i, city_bit | (1 << i), max_city, graph, memo, memo_r, lower_deque_local);             if (lowest_result > new_lower) {                 lowest_result = new_lower;                 temp_route = lower_deque_local;                 temp_route.push_front(i);                 //consider replace deque_reference better lower_deque                 //add node came                 deque_reference = lower_deque_local;                 deque_reference.push_front(i);             }             //lowest_result = min(lowest_result, graph[pos+1][i+1] + held_karp(i, city_bit | (1 << i), max_city, graph, memo));         }     }     memo[pos][city_bit] = lowest_result;     memo_r[pos][city_bit] = temp_route;     //printf("%d 3^\n",pos);     return lowest_result; }  int main(int argc, char * argv[]) {     vector<vector<double>> graph (1000, vector<double>(1000 , 0));      //set max_city - 0 not used     int max_city = fillgraph(graph,argv[1]);     vector<vector<double>> memo (max_city, vector<double>((1<<(max_city))-1, -1));     vector<vector<deque<int>>> memo_r (max_city, vector<deque<int>>((1<<(max_city))-1));     deque<int> route;      clock_t tstart = clock();      double time = held_karp(0, 1, max_city, graph, memo, memo_r, route);      //print out     printf("optimal tour length: %f\n", time);      printf("tsp tour:\n");     //printf("1\n");     int size = (int)route.size();     (int = 0; < size; i++) {         printf("%d\n",(route.back()+1));         route.pop_back();     }     //printf("1\n");      printf("total time elapsed: %fs\n", (double)(clock() - tstart)/clocks_per_sec);  } 

when walk though execution in xcode can see data not copied memo_r[x][y] temp_route. index data should shows, displayed in ide empty. when click 'more info' see <could not resolve type> message.