identification the location of objects

edit

Hello dears, i am new in ROS and i have tried to detect objects by laser fortunately i could do some things, i mean if i want to find objects in Left, Right or Front separately, i am done, but when i am going to mix all, consider each of them as a function, unfortunately just one of them is working. may i ask you please take look at my code and help me. (my question find location of the object)

 int check_Left()
{

    double total_index = (laser.angle_max + abs(laser.angle_min))/laser.angle_increment;

    for (int i =680 ; i < total_index  ; i++)
        {
            if( laser.ranges[i] < 8)
            {
                state = 9;
            }
            else
            {
                state =0;
                break;
            }
        }

    return state;
}




int check_Right()
{   for (int i =0 ; i < 50 ; i++)
        {
            if( laser.ranges[i] < 9)
            {
                state = 3;
            }
            else
            {
                state =0;
                break;
            }
        }

    return state;
}



int check_fornt()
{

    for (int i = 320; i < 400 ; i++)
    {
        if( laser.ranges[i] < 9)
        {

            state = 12;
        }
         else
        {
            state = 0;
        }
    }

    return state;
}





void scanCallback(const sensor_msgs::LaserScan scan)
{

    laser = scan;

     state = check_Right();
     Duration(0.25).sleep();
     state = check_Left();

     Duration(0.25).sleep();
     state = check_fornt();
     Duration(0.25).sleep();
     cout << state << endl;
    /* switch (state) {
        case 12:
            cout << "object is in Front"<< endl;
            break;
        case 3:
            cout << "object is in Right"<< endl;
            break;
        case 9:
            cout << "object is in Left"<< endl;
            break;

    }
*/

}




 int main(int argc, char **argv)
 {
     init(argc ,argv , "Obstacle_avoidance");
     NodeHandle n;
     Com_sub = n.subscribe("scan",10,scanCallback);
     Com_pub =n.advertise<geometry_msgs::Twist>("cmd_vel",10);

     spin();

     return 0;
}