I am making a console based database system. Because I have to keep inserting, editing , deleting data blocks from my record file I have decided to use either vectors or list to store the all records. From the file I shall read the entire vector/list and work with it to add , remove or edit record and then again write the entire vector/list to the file again. I figured it would stop all the weird things that happen when directly working with the file. Is it an efficient way ?Or is it totally unnecessary ?Is there a better way?
i am trying to make a simple log in system without the use of database or whatever it is called.
my only concern is this
cout<<"enter password:"; cin>>pass;
how would i be able to make the characters appear as **** rather than the actual character that i would type as i am typing my password in CIN? or is it even possible?
Which is best option to save images in database or file system, I am developing c++ server client app. I want to save the images in server using file system or database. I am confusing to choose which option?
I wrote an application with wpf and c sharp. And I use ado dotnet framework to connect the database. Now the problem is I want a centralize database for the application. And I hav e installed sql server on one of the which I want to serve as server. I now want all other clients to be able to connect to the database through local area network. how will I do that?
I've remade a program to store student database using linked list. When I try to display the list of student with their information (It displays nothing)
I wanted to retrieve all rows from database and display in listview using list<string>
con.Open(); MySqlCommand view = new MySqlCommand("Select Cust_ID,Fname,Mname from Customer;", con); MySqlDataReader v1 = view.ExecuteReader(); while (v1.Read()) { for (int i = 0; i < v1.FieldCount; i++){ result.Add(v1["Cust_ID"].ToString());
I want to display the content of my database in list view. The table has 5 columns however when I tried this code
string view = "Select * from cust_infor"; SqlCommand cmd = new SqlCommand(view,FL.clsconnection.opencon()); SqlDataReader dr = cmd.ExecuteReader(); listView1.Items.Clear(); while (dr.Read()) { listView1.Items.Add(dr[0].ToString()).SubItems.Add(dr[1].ToString()); }
It limits the display to 2 columns. List view will only show the first 2 columns. The code above won't let me add more indexes or subitems. Only up to 2 columns.
This code worked perfectly fine in Xcode earlier today, but when I got home on visual studio 2012 express it is having an error. It's saying that the local function definitions are illegal and has a red mark under the '{' only?
How can I write my own container which has properties of both vector and list.
E.g. I can access elements directly using [] operator like vector and behave like list in terms of memory (means we don't have to shift elements if we want to insert in between like list)....
I was assigned to print a linked list but as a vector of char (I cannot use the normal string type) , this is what I have:
char* List::asString(){ Node* ite = new Node(); ite= first;//ite is like an iterator of the list for(int i=0; i<sizeOfList; ++i){//sizeOfList is the total of node of the list
[Code] ....
But when I print that, I get a bunch of weird symbols...
I am making a simple program that is suppose to make a list of champions and their items from the game League of Legends. I am stuck on making a vector of the class so each slot within the vector would hold each champion and its data. This is what I got:
Champion_Info.h
#ifndef CHAMPION_INFO_H_INCLUDED #define CHAMPION_INFO_H_INCLUDED #include <vector> #include <string> using namespace std; class Champ_Info
void armazenaFA( std::vector <int> &vFA) // this function only knows about vFA { vsFA[n] [m]= simTime().dbl(); OR vsFA[n].push_back(simTime().dbl()); }
How to output vector contents using the push_back function. My program reads in values just fine, but it does not output anything and I've been stuck on why.
here is my code:
#include <iostream> #include <array> #include <vector> using namespace std; int duplicate( vector < int > &vector1, const int value, const int counter)
I have a cpp app that reads in a number of files and writes revised output. The app doesn't seem to be able to open a file with a ' in the file name, such as,
N,N'-dimethylethylenediamine.mol
This is the function that opens the file :
Code: // opens mol file, reads in rows to string vector and returns vector vector<string> get_mol_file(string& filePath) { vector<string> mol_file; string new_mol_line; // create an input stream and open the mol file ifstream read_mol_input; read_mol_input.open( filePath.c_str() );
[Code] ....
The path to the file is passed as a cpp string and the c version is used to open the file. Do I need to handle this as a special case? It is possible that there could be " as well, parenthesis, etc.
I have asked a related question before, and it was resolved successfully. In the past, when I wanted to use std::max_element in order to find the maximum element (or even sort by using std::sort) of a vector of structures according to one of the members of the structure, all I had to do was to insert a specially designed comparison function as the third argument of the function std::max::element. But the latter comparison function naturally accepts two arguments internally.
For instance, here is a test program that successfully finds the maximum according to just one member of the structure:
And the output was this, as expected: Maximum element S.a of vector<S> vec is at: 9 [I]max element of vec.a between slot 3 and slot 6 is: 6, and its index is: 6 vec[6].a = 6 [I]max element of vec.a between slot 4 and slot 7 is: 7, and its index is: 7 vec[7].a = 7 [I]max element of vec.a between slot 5 and slot 8 is: 8, and its index is: 8 vec[8].a = 8 [I]max element of vec.a between slot 6 and slot 9 is: 9, and its index is: 9 vec[9].a = 9
However, I now need to search and find an element of vector<myStruct> according to just one member of myStruct, instead of finding the maximum or sorting as before. This presents a problem because the function std::find does not accept such a comparison function as its third argument.
This was the description of the std::find function that I found: find - C++ Reference
Code: template <class InputIterator, class T> InputIterator find (InputIterator first, InputIterator last, const T& val);
I could also find another function called std::find_if, but this only accepts a unary predicate like this: find_if - C++ Reference
Code: template <class InputIterator, class UnaryPredicate> InputIterator find_if (InputIterator first, InputIterator last, UnaryPredicate pred);
And once again this is either inadequate of I don't see how to use it directly, because for the third argument I would like to insert a function that takes two arguments with a syntax like this:
Code: int x=7; std::vector<S>::iterator result; result = std::find(vec.begin(), vec.end(), []( const (int x, const S & S_1) { return ( x == S_1.a ) ; } ) ;
Is there another std function that I can use to make search and find an element according to just one member of myStruct?
Or perhaps there is a clever way to pass two arguments to the unary predicate.
I am trying to print a matrix solution that I've stored in a vector of doubles. The original matrix was stored in a vector of vector of doubles. I want to print to the screen and an output file. Right now it just prints to screen column-style and the output file is horizontal-style. I tried to change the solution from vector of doubles to a vector of vector of doubles like the original matrix but when I run my code it crashes. Here is what I am referring to:
void readMatrix(vector<vector<double>> &matrix, vector<double> &b, int &N, string input) { ifstream in(input); in >> N; matrix.resize(N); b.resize(N);
[Code] ....
However when I change my printResult function to this (I removed the string argument because I just want to get it working to the screen first):
void printResult(vector<vector<double>> &sol, const int N) { //ofstream out(output); //int j; for (int i = 0; i < N; i++) { for (int j = 0; j < N; j++){
[Code] ....
The program crashes. Am I even printing the matrix correctly?
I want to have it so that when i ask for the person witch item they want to drop on the ground it goes into another vector that i can pick back up the item if they want it back and erase when they walk away.
Why is it reading in nothing for the arrays, and also making the size of the total thing the total number of numbers? It should have a size of 2, not 5.
std::vector<unsigned char> vec1; //insert some values into vec1 std::vector<unsigned char> vec2;
Now I want to to copy 2 bytes from vec1 starting at index 5., why do i need to know how many bytes from the end of vec1?? can't i just specify how many bytes i want to copy from starting index?
