I have an integer vector of size "n".
e.g.
std::vector<int> vec;
vec.pushback(0);
vec.pushback(1);
vec.pushback(2);
vec.pushback(3);
Now I want to generate all possible combinations of size = {0, 1, 2, ... , n}.
{0, 1, 3} is not equal to {3, 1, 0} or {1, 0, 3} or {3, 0, 1}
I'm writing a program with a class containing a private std::vector<bool>. I chose bool because the vector represents a 2D array (think grid) and I only need 2 states per cell. I kept it one-dimensional as this hardly complicates things.
My problem is that I don't know how to initialize the vector, i.e. fill it with 0's.
The grid's resolution is not known at compile time, so I imagine I have to set the size (and content) of the vector in the class constructor.
Here's what I have tried among several things:
Code: World::World(const u_short worldsize)
{
grid.reserve(worldsize * worldsize); // grid is the private vector; square dimensions.
std::fill(grid.begin(), grid.end(), 0);
std::cout << grid.size();
} The output is 0. Only std::vector::push_back seems to have an effect on size(), but judging by its description, it doesn't look like the right candidate to populate a vector with zeros. Correct me if I'm wrong.
Frankly I expected line 3 to set the vector's size.
how to swap the first and 'mid' elements of a vector?
View 2 Replies View RelatedI had a question about memory allocation/how iterators work for a std::vector<foo> of a user defined class 'foo'. Say foo contains variables of variable size, so that each member of the std::vector<foo> does not require the same amount of memory space.
Does c++ allocate the same amount of memory for each element, equal to the amount of memory required for the largest element? Or does it use some sort of array of pointers pointing to the location of each element in the vector to make the iterator work? Or does it use some other method? I am wondering because I wrote a code which reads data from a binary files and stores most of it in std::vectors.
The code seems to be using significantly more memory than the sum of the size of all the binary files, and I am using vectors made up of the datatype within the binary files (float). So I was wondering if internally the code was allocating space for each vector element which is the size of the largest element as a way to handle indexing/iterators. I ran my code through a memory leak checker and it found no errors.
I am currently trying to implement a 2d vector to store x and y of type int.
I have successfully passed it to the function, however i am unable to store the values in it. It always returns with a segmentation fault and my program terminates from there. May i know how do i store them properly and call them out?
Below is my code snippet
int reconstructSecret(int x, int y, vector< vector<int> > &inVec ,int constructSecret) {
int getX,getY,formula,accum,count,getSecret,startPosition,nextPosition,numerator,denominator;
getX=x;
getY=y;
int result;
[Code] .....
The main method
vector< vector<int> > inVec;
for(int i=0;i<constructSecret;i++) {
cout<<"please key in the "<<i<< "share of x value:";
cin>>x;
[Code] ...
I am working on a project for class where I use a parent Shape class with circle, rectangle, ect. Classes inheriting from that. Along side these I use a class called Scene. In main I need to create a scene and add some shapes to a vector in scene.
vector<Shape*> shapes
I need to use functions addShape(Shape* shape) and a delete shape method. I have the addShape finished. The problem I am having is with the delete method. Is there a way that I can use something like deleteShape(Shape* shape)? Is it possible for me to delete a specific shape from the vector by passing in that shape, or can it only be done using index? I have looked at the documentation for std::vector as well as std::vector::erase. I am wondering this because if I use index values and do something like
void Scene::deleteShape(unsigned int x) { shapes.erase(shapes.begin() + x ); }
It will lead to some errors later on due the the changing size and indexes of the vector and elements.
so lets assume i have a nested vector in a set or vice versa o in a more general form a container in a container example...
Code:
std::set<vector<int> > my_tuple;
How do i access individual elements of lets say the first vector in the set! Or the last element in the 3rd vector?
here is a piece of my code:
while(T--)
{
std::vector<std::pair<int, int> > *dragon;
std::vector<std::pair<int, int> > *villager;
[Code]....
I now wish to print the elements of the vector. How do I do it?
"Write a declaration for a function that takes two int parameters and returns an int, and declare a vector whose elements have this function pointer type."
View 9 Replies View RelatedI think std::copy appears to do what I'm looking for.
I'm in need of a vector member function that would allow me to "insert" a number of elements from one vector into another vector without resizing or destroying either.
An example of what I'm wanting to do is assign the contents of two[3-5][50-54] to one[7-9][2-6]. Other than looping through both vectors using .at(), is there a way to copy this?
This would be continuous within a user controlled loop with differing elements being exchanged.
typedef vector<vector<unsigned char> > vec;
vec one(10, vector<unsigned char>(10, '1')),
two(90, vector<unsigned char>(90, '2'));
I have read that the Erase-remove idiom is the way to go. I have a rough understanding of how this works but am unsure whether I can implement a match-counter along with it.
For counting alone, I would use something like this:
Code:
std::vector<std::string> v; // contains duplicate strings in different elements
std::string term = "foo"; // search term, changing at runtime as well
unsigned int matches = 0;
for( auto e : v ) {
if( e == term ) {
[Code] .....
I'm not sure how (or if) I can combine the two things. That is, I don't know how to integrate a function comparing two (changing) strings into the remove_if() method. Nor do I know how to increment a counter during iteration.
The vector is extremely large, so speed is paramount. I think there are many other avenues for optimization, but decreasing the vector's size for each consecutive search could deliver a big speed boost for subsequent searches I imagine, as traversing it holds the biggest cost.
write a swap function to swap 2 elements in the vector?
View 3 Replies View RelatedA few days ago I got a "bright idea" to see if I could match a string, with an arbitrary length from 1 to 12, to its formulated sequence by using an algorithm to find all possible combinations of the integer combinations from 0 to 9 at each length (1 to 12).
Example: Desired numerical combinations from integers 1 to 3:
At Length 1:
1, 2, 3
At Length 2:
11, 12, 13, 21, 22, 23, 31, 32, 33
At Length 3:
111, 112, 113, 121, 122, 123, 131, 132, 133, 211, 212, 213, 221, 222, 223, 231, 232, 233, 311, 312, 313, 321, 322, 323, 331, 332, 333
And so on until the nth length (in my case a length of 12).
First off, I would like to say that this is not as easy as I thought. I clearly underestimated the problem seeing as I've spent hours attempting to write a working algorithm, but feel like I've made no progress.
Here are a few of my attempts:
Attempt 1:
#include <iostream>
#include <algorithm>
#include <math.h>
#include <string>
[Code]....
I can't exactly explain this one. It works if the length is 2 or less; however, the order of the output is horrendous.
Attempt 3: I tried using recursion, but only found myself getting more and more lost the further I tried developing my function. Cannot find my work for this attempt.
I would really like to figure this out on my own, but I am very stuck as you can see. I also lack time that I can spend working on this since im a full time student.
I need to create a function that outputs all possible binary combinations. I'm really stumped on this. I have to do it with nested loops, and am not sure how to go about it. Below is what I tried so far.
The output should look like this:
00000000
00000001
00000010
00000011
00000100
...
11111110
11111111
Code:
void outputBinary(){
int a[2][2][2][2][2][2][2][2];
for (int i = 0; i < 2; i++){
for (int j = 0; j < 2; j++){
[Code] .....
I wanted to create a 5, 3 combinations. i know how to calculate to get the number of combinations 5 3 would have (which is ten), but it seem it's a bit harder for me to print those data ...
View 2 Replies View RelatedHow to find all possible combinations of coordinates on a 2d grid with a given sum. The sum is not fixed!
E.g. N=nxm=25 thats our grid.
The sum=distance between points on a grid.
For two points distance=|(x1-x2)+(y1-y2)| point A(X1,Y1) B(X1,Y1)
My interest is to know how to find the combinations of coordinates with a given sum, it doesn't matter how many points are there.
If i enter the sum e.g sum=7 and the program has to show all possible combinations which gives the sum of 7 the number of point does not play in row they might be two or maybe more.
I create a list of vectors (a vector of n vectors of m elements).
std::vector <std::vector <int> > vsFA (n, std::vector<int>(n));
How I assign values? I try below, but not worked
void armazenaFA( std::vector <int> &vFA) // this function only knows about vFA
{ vsFA[n] [m]= simTime().dbl();
OR
vsFA[n].push_back(simTime().dbl());
}
Code:
#include<stdio.h>
#include<string.h>
#define a 15
[Code]....
I am trying to print all combinations of a string but I couldn't figure out how to do loop for it. Code works only 2-3-4 letters words
I am trying to write a program for printing all the combinations of a string. Why this program is giving the error message.
"First-chance exception at 0x761bc41f in word.exe: Microsoft C++ exception: std::out_of_range at memory location 0x0026f6b4..
Unhandled exception at 0x761bc41f in word.exe: Microsoft C++ exception: std::out_of_range at memory location 0x0026f6b4.." when i try to run this in MVS 2010
#include<iostream>
#include <stdio.h>
#include <string>
#include <stdlib.h>
#include<conio.h>
void combination(std::string input,int length,std::string buffer,int allowedno)
[Code] .....
How to get all the possible combinations for 4 digits from a 5 digit number. I need a pair that has both 5 digits and four digits. their sum must be equal to a five digit user input. i.e.
user input : 14690
output:
14690 has pairs 12345 + 2345
2345 came from 12345
lets say that x = 12345 and y =2345
besides y == x%10000
other formula can i have since if i use % and / i will have a lot of declarations....
how to write a password cracking program that will try all possible char combinations for just two chars (without duplicating any combination guesses). Obviously, there would only be 4 possible truth table combinations for two boolean values, but how would a person calculate the number of all possible combinations for two values with 70 different possible chars?
#include <iostream>
#include <string>
#include <cstdlib>
#include <ctime>
using namespace std;
static const char alphanum[] =
"0123456789"
"!@#$%^&*"
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz";
/*
Boolean Truth Table for two values:
p q
-----
T T
T F
F T
F F
Note that there are 70 chars in all specified above.
It will require much more than a simple truth table to try every possible char combination (especially if the password to be cracked is 2 or more chars). Using this guy's code: [URL] ..... as a starting point, I'm writing a program that will crack a password with a length of just 2 chars.
*/
int stringLength = 2;
char genRandom() {
return alphanum[rand() % stringLength];
}
int main() {
std::string password = "Sp";
srand(time(0));
std::string Str;
[code]....
The first line of my input file is going to contain some number "T" which will represent the "combination length" of a list of random words. (In this case, they are Taco Bell items). The first number on the second line represents the number of unique items on the menu to get, and the second number on the second line represents the number of unique items that are supposed to be bought.
Basically the input will look like this: 2 3 2 taco burrito nacho
And the output looks like this: burritos nachos nacho taco burrito taco
This is what I have so far:
Code:
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
int main(void){
int N, T, K;
char menu[N][20];
[Code] .....
What I am trying to get working right now is just to scan a file and put the strings into an array so then I can work on sorting the array. How can I add strings from a file into an array?
Coding for- To print all combinations of numbers that can compose a given number..
View 3 Replies View RelatedI've been experimenting a bit and can't find a decent way to make a brute forcing script that accepts a password from standard input, and goes through all possible combinations until it is matched. How to structure the code?
View 1 Replies View RelatedI have this program for generating subsets, I need to run it with input n=23. It has been running for the past 5 hours, is it normal???
Code:
/*generate subsets */
int subsets(vector < bool > sub, int i)
{
if (i > n) {
return 0;
[Code] .....
I have a program that generates random numbers. After the random number is generated, the program asks if you want to generate another random number. However, if you generate another random number, it is always the same as the first random number. How can I fix this?
View 5 Replies View Related