Why does my code perform the later cout first? - c++

The following code
#include "stdafx.h"
#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
using namespace std;
bool checkPerm(unsigned long long x){
vector<unsigned long long> tester;
string strx = to_string(x);
int sizestrx = strx.size();
int counter = 1;
cout << "x is " << strx << " and its permutations are ";
while (next_permutation(strx.begin(), strx.end())){
cout << strx << " ";
unsigned long long stoipermstrx = stoi(strx);
tester.push_back(stoipermstrx);
}
cout << endl;
int sizetester = tester.size();
for (int j = 2; j <= 6; j++){
cout << "j is " << j << ' ';
for (int k = 0; k < sizetester; k++){
if (j*x == tester[k]){
cout << "counter increased because x, counter " << x << " " << counter << endl;
counter++;
if (counter == 6){
cout << "Number is " << x << endl;
return true;
}
break;
}
}
//cout << "Number " << x << " failed" << endl;
return false;
}
return true;
}
int main(){
unsigned long long x = 1;
for (double i = 0; ; i++){
cout << i << endl;
while (x < 1.67*pow(10, i)){
if (i == 5)
cout << x << endl;
if (checkPerm(x)){
cin.get();
}
x++;
}
x = pow(10, (i + 1));
}
cin.get();
}
has the following problems in this piece of code:
cout << "x is " << strx << " and its permutations are ";
while (next_permutation(strx.begin(), strx.end())){
cout << strx << " ";
unsigned long long stoipermstrx = stoi(strx);
tester.push_back(stoipermstrx);
}
cout << endl;
int sizetester = tester.size();
for (int j = 2; j <= 6; j++){
cout << "j is " << j << ' ';
for (int k = 0; k < sizetester; k++){
if (j*x == tester[k]){
cout << "counter increased because x, counter " << x << " " << counter << endl;
counter++;
if (counter == 6){
cout << "Number is " << x << endl;
return true;
}
break;
}
}
//cout << "Number " << x << " failed" << endl;
return false;
}
Here the output will be "j is j x is x and its permutations are (permutations of x)". HOWEVER, the console should print "x is x and its permutations are (permutations) j is j". The following sample output is given:
j is 2 x is 1355 and its permutations are 1535 1553 3155 3515 3551 5135 5153 531
5 5351 5513 5531
j is 2 x is 1356 and its permutations are 1365 1536 1563 1635 1653 3156 3165 351
6 3561 3615 3651 5136 5163 5316 5361 5613

It appears there are two (minor) things about this. One, you are not looking at the value of sizetester before printing the value of j, and you are not printing a newline after the value of j. This means you are displaying the value of j for the previous loop at the beginning of your line for the current 'x'. If I understand what your code is supposed to be doing, it seems to be doing it correctly -- it's just the way that the output is getting displayed that makes it confusing.
Try this:
int sizetester = tester.size();
for (int j = 2; j <= 6; j++){
if (sizetester){ // <-- added test (see below)
cout << "j is " << j << '\n'; // <-- added newline
} // <--
The test against sizetester suppresses spurious printings of values for j - you later test that (k < sizetester) anyway. The newline just prevents values of j from starting the line for the next values of x, which appears to be the cause of the confusing output.

Related

Nested For - Loops to create multiplication table C++

I've been trying to overcome this problem for a few hours now and I seem to have one approach to the situation. It seems that the use of selection statements worked in creating the table necessary. Although there are formatting issues.
I'd like to know if there was a way to create the same table
using only nested for-loops as mentioned by our professor.
Are the selection statements necessary or can we implement a system of nested for loops to acquire the same results?
The image below is the required table:
But the image below is what I have:
Below is my code:
for (int i = 0; i <= numChoice; ++i)
{
if (i == 0)
{
for (int k = 1; k <= numChoice; ++k)
{
cout << " " << k;
}
cout << "\n";
}
else
{
cout << i << " | ";
for (int j = 1; j <= numChoice; ++j)
{
if (j*i <= 9)
{
cout << " " << j*i << "|";
}
else if (j*i > 9 && j*i <= 100)
{
cout << " " << j*i << "|";
}
else if (j*i > 99 && j*i <= 999)
{
cout << " " << j*i << "|";
}
}
cout << "\n";
for (int k = 0; k <= numChoice; ++k)
{
if (k == 0)
{
cout << "-|";
}
else
{
cout << "----|";
}
}
cout << "\n";
}
}
The following code uses no if else constructs. The formatting can be got by using setw, used for setting the width of integers.Following code produces perfect output.
#include<iostream>
#include<iomanip>
using namespace std;
int main()
{
int i,j;
cout<<" "<<1;//5 space chars
for(i = 2;i <= 10;++i)
cout<<" "<<i;//4 space chars
cout<<endl;
cout<<" ----|";
for(i = 2;i <= 10;++i)
cout<<"----|";
cout<<endl;
for(i = 1;i <= 10;++i)
{
cout<<setw(2)<<i<<"|";
for(j = 1;j <= 10;++j)
cout<<setw(4)<<j*i<<"|";
cout<<endl;
cout<<" -|----";
for(j = 2;j <= 9;++j)
cout<<"|----";
cout<<"|----|";
cout<<endl;
}
return 0;
}
#FranticCode. I'm also in the same class as you and was having problems with this homework assignment as well. I still don't understand it, but I figured out how to manipulate Sumeet's code to give us correct format. The ONLY thing I am having a problem with now is adding an empty space AFTER the first multiplication table and before the menu redisplay. I'll share what I have and maybe you can figure it out. Still going to ask the professor to review chapter 5 because I would like to learn it rather than just submit the homework.
#include <iostream>
#include <iomanip>
#include <string>
#include <cstdlib>
#include <ctime>
using namespace std;
int main()
{
char userSelection;
int numForTable;
int col;
int row;
do
{
cout << "MENU" << endl
<< "a) Generate Multiplication Table" << endl
<< "q) Quit the program" << endl
<< "Please make a selection: ";
cin >> userSelection;
if (userSelection == 'a')
{
cout << "Please enter a number for your multiplication table: " << endl;
cin >> numForTable;
while (numForTable < 1 || numForTable > 10)
{
cout << "Please enter a number between 1 & 10." << endl;
cin >> numForTable;
}
cout << "\n"
<< "MULTIPLICATION TABLE: " << numForTable << "'s" << endl
<< "\n"
<< " " << 1;
for (col = 2; col <= numForTable; ++col)
cout << " " << col;
cout << endl;
cout << " ----|";
for (col = 2; col <= numForTable; ++col)
cout << "----|";
cout << endl;
for (col = 1; col <= numForTable; ++col)
{
cout << setw(2) << col << "|";
for (row = 1; row <= numForTable; ++row)
cout << setw(4) << col * row << "|";
cout << endl;
cout << " -|----";
for (row = 2; row <= numForTable - 1; ++row)
cout << "|----";
cout << "|----|";
cout << endl;
}
}
else if (userSelection != 'q')
{
cout << "Invalid Selection\n" << endl;
}
else if (userSelection == 'q')
{
cout << " You have chosen to quit the program. Thank you for using!" << endl;
}
}
while (userSelection != 'q');
//system("PAUSE");
return 0;
}
got curious to see if i could add the lines as easy as i claimed, it took a bit of fiddling, but here's the result (updated code below to also have lines).
#include <iostream>
#include <iomanip>
using namespace std;
int main(){
int counter;
int counter2;
int amount;
cout << " |-----------------------------------------------------------|" << endl; // first line of table.
for(counter=1;counter<11;counter++){ // the 2 for lines create our 2 dimensional table
for(counter2=1;counter2<11;counter2++){
cout << " | " << setw(3) << counter*counter2; // setw(3) is a function of <iomanip>,
//setting minimum width to 3 for numbers.
}
cout << " |" << endl; // this here is being added to the end of each line and starts a new line.
cout << " |-----------------------------------------------------------|" << endl; // this is being inserted between each line, and starts a new line.
}
return 0;
}
Use the following construct:
for (int i=0; i<=numChoice; i++) // display first row of numbers
cout <<"\t" << i << "\t";
cout << "\n";
for (int i=0; i <=numChoice; i++) {
cout << i << "\t";
for (int j=0; j <=numChoice; j++)
cout << i*j << "\t";
cout << "\n";
}

Unhandled exception at 0x012B1CA9

I am new to C++ and am trying to build a simple program that with the users input to proceed will generate a random left or right. I had the program working correctly until I added in the array to try and store each item as I have to output them as soon and the user would like to exit the loop. The program seems to compile fine but at run time I receive "Unhandled exception at 0x012B1CA9" Any help would be greatly appreciated.
#include <iostream>
#include <ctime>
using namespace std;
int main()
{
int userSelection = 1;
const int MAX = '100';
int randNum(0);
int one (0);
int two (0);
int total(0);
int sel[MAX];
do
{
cout << "Press 1 to pick a side or 0 to quit: ";
cin >> userSelection;
for (int i = 1; i < MAX; i++)
{
srand(time(NULL));
sel[i] = 1 + (rand() % 2);
if (sel[i] == 1)
{
cout << "<<<--- Left" << endl;
one++;
total++;
}
else
{
cout << "Right --->>>" << endl;
two++;
total++;
}
}
} while (userSelection == 1);
cout << "Replaying Selections" << endl;
for (int j = 0; j < MAX; j++)
{
cout << sel[j] << endl;
}
cout << "Printing Statistics" << endl;
double total1 = ((one / total)*100);
double total2 = ((two / total)*100);
cout << "Left: " << one << "-" << "(" << total1 << "%)" << endl;
cout << "Right: " << two << "-" << "(" << total2 << "%)" << endl;
system("pause");
return 0;
};
You have a multi-character constant here... and the behavior doesn't go as expected...
Change this line
const int MAX = '100';
to
const int MAX = 100;
Note the removed single quotes.
And secondly, I will advice you to remove the Seed of the C random generator from the for loop because, you'll likely get the same values from the rand() if you always call it immediately after seeding...
But preferable use the algorithm from C++'s random header
Here is a corrected version of your original code....
#include <iostream>
#include <ctime>
using namespace std;
int main()
{
int userSelection = 1;
const int MAX = 100; // <---changed
int randNum(0);
int one (0);
int two (0);
int total(0);
int sel[MAX];
do
{
cout << "Press 1 to pick a side or 0 to quit: ";
cin >> userSelection;
srand(time(NULL)); //< moved to here
for (int i = 0; i < MAX; i++) // <-- modified starting index
{
sel[i] = 1 + (rand() % 2);
if (sel[i] == 1)
{
cout << "<<<--- Left" << endl;
one++;
total++;
}
else
{
cout << "Right --->>>" << endl;
two++;
total++;
}
}
} while (userSelection == 1);
cout << "Replaying Selections" << endl;
for (int j = 0; j < MAX; j++)
{
cout << sel[j] << endl;
}
cout << "Printing Statistics" << endl;
double total1 = ((one / total)*100);
double total2 = ((two / total)*100);
cout << "Left: " << one << "-" << "(" << total1 << "%)" << endl;
cout << "Right: " << two << "-" << "(" << total2 << "%)" << endl;
system("pause");
return 0;
};
I think that it is basically good idea to read more about C data types and declaration. Your error:
const int MAX = '100' should be const int MAX = 100 without any quotes. C++ does implicit conversion from character literals to int.

Resizing a dynamic bitset in C++ to a length entered by the user

This C++ program asks the user to enter the length of the bit sequence he/she will enter next. This length variable is named xx, it is of type int. I am using three dynamic bitset with the initial size of 5, these are inpSeq, operSeq and bit. I am resizing the bitsets by
inpSeq.resize(xx); for example. When compiling the program, a very big list of errors appears, I feel I can't paste it here. but I am sure that these errors are all related to this variable xx, the code was compiled fine before using it as a variable to resize the bitset. What is wrong with the way I am resizing the bitset? And can I make the bitsets of the size of inpSeq without asking the user to enter the length of inpSeq bitset?
#include <iostream> //Standard library.
#include <boost/dynamic_bitset.hpp> //Library for 10 handling.
#include <vector> //Variable size array.
#include <algorithm> //We use sorting from it.
using namespace std;
int main()
{
int y = 0;
int turnCount = 0;
int count1 = 0, count0 = 0;
int xx = 0;
boost::dynamic_bitset<> inpSeq(5);
int polyLoc;
boost::dynamic_bitset<> operSeq(5);
boost::dynamic_bitset<> bit(5);
vector <int> xorArray;
vector <int> keyReg;
cout << "What is the legnth of the sequence?";
cin << xx;
inpSeq.resize(xx);
operSeq.resize(xx);
bit.resize(xx);
cout << "Enter a bit sequence: \n";
cin >> inpSeq;
int seq_end = inpSeq.size() - 1;
cout << "Enter polynomial:";
cin >> polyLoc;
while(polyLoc>0)
{
xorArray.push_back(polyLoc%10);
polyLoc/=10;
}
cout << "xorArray is: ";
for ( unsigned int i = 0; i < xorArray.size(); i++)
{
cout << xorArray[i] << " ";
}
sort(xorArray.rbegin(), xorArray.rend());
cout << "\n";
operSeq = inpSeq;
keyReg.push_back(inpSeq[0]);
int x = xorArray[0];
cout << "x is: " << x << "\n";
for ( unsigned int i = 0; i < xorArray.size(); i++)
{
cout << xorArray[i] << "\n";
}
cout << "bit 3 of initial " << bit[seq_end] << "\n";
do {
for (unsigned int r = 1; r < xorArray.size(); r++)
{
bit[seq_end] = operSeq[x];
y = xorArray[r];
bit[seq_end] = bit[seq_end] ^ operSeq[y];
}
operSeq >>= 1;
operSeq[seq_end] = bit[seq_end];
keyReg.push_back(operSeq[0]);
turnCount ++;
cout << "--\n";
}
while ((operSeq != inpSeq) && (turnCount < 20));
cout << "Generated key is: ";
for (unsigned int k = 0; k < keyReg.size(); k++)
{
cout << keyReg[k];
}
cout << "\n";
cout << "Bit 1 positions: ";
for ( unsigned int g = 0; g < xorArray.size(); g++)
{
cout << xorArray[g];
}
cout << "\n";
cout << "Key length is: " << keyReg.size();
cout << "\n";
for ( unsigned int i = 0; i < keyReg.size(); i++)
{
if (keyReg[i]==1)
{
count1++;
}
else {
count0++;
}
}
cout << "Number of 0's: " << count0 << "\n";
cout << "Number of 1's: " << count1 << "\n";
if ( keyReg.size()%2 ==0)
{
cout << "key length is even. \n";
if (count1==count0)
{
cout << "Key is perfect! \n";
}
else {
cout << "Key is not perfect! \n";
}
}
else
{
cout << "key length is odd. \n";
if ((count1==count0+1) || (count0==count1+1))
{
cout << "Key is perfect! \n";
}
else {
cout << "Key is not perfect! \n";
}
}
cin.get();
}

A variable length bitset in C++ [duplicate]

This question already has answers here:
Define bitset size at initialization?
(7 answers)
Closed 5 years ago.
I have a working 4 bit linear feedback shift register, using 3 bitsets of length 4: inpSeq, operSeq and bit. I want to make the program accept a variable length bit sequence, so those previous bitsets should be of variable length somehow. The user may enter a sequence ofr inpSeq and the program sets the three bitsets to be of the same length as that sequence provided by the user. Any ideas for how to achieve this? Sample code if I may ask!
Here is the code:
#include <iostream> //Standard library.
#include <bitset> //Library for 10 handling.
#include <vector> //Variable size array.
#include <algorithm> //We use sorting from it.
using namespace std;
int main()
{
int y = 0;
int turnCount = 0;
int count1 = 0, count0 = 0;
bitset <4> inpSeq;
int polyLoc;
bitset <4> operSeq;
bitset <4> bit;
vector <int> xorArray;
vector <int> keyReg;
cout << "Enter a 4-bit sequence: \n";
cin >> inpSeq;
cout << "Enter polynomial:";
cin >> polyLoc;
while(polyLoc>0)
{
xorArray.push_back(polyLoc%10);
polyLoc/=10;
}
cout << "xorArray is: ";
for ( unsigned int i = 0; i < xorArray.size(); i++)
{
cout << xorArray[i] << " ";
}
sort(xorArray.rbegin(), xorArray.rend());
cout << "\n";
operSeq = inpSeq;
keyReg.push_back(inpSeq[0]);
int x = xorArray[0];
cout << "x is: " << x << "\n";
for ( unsigned int i = 0; i < xorArray.size(); i++)
{
cout << xorArray[i] << "\n";
}
cout << "bit 3 of initial " << bit[3] << "\n";
do {
for (unsigned int r = 1; r < xorArray.size(); r++)
{
bit[3] = operSeq[x];
cout << "bit 3 from prev: " << bit[3] << "\n";
y = xorArray[r];
cout << "opseq[y] is: " << operSeq[y] << "\n";
bit[3] = bit[3] ^ operSeq[y];
cout << "bit[3] after xor: " << bit[3] << "\n";
}
operSeq >>= 1;
cout <<"operSeq after shift: " << operSeq << "\n";
operSeq[3] = bit[3];
cout <<"opserSeq bit 4 after = bit[3]: " << operSeq[3] << "\n";
cout <<"new operSeq: " << operSeq << "\n";
keyReg.push_back(operSeq[0]);
turnCount ++;
cout << "--\n";
}
while ((operSeq != inpSeq) && (turnCount < 20));
cout << "Generated key is: ";
for (unsigned int k = 0; k < keyReg.size(); k++)
{
cout << keyReg[k];
}
cout << "\n";
cout << "Bit 1 positions: ";
for ( unsigned int g = 0; g < xorArray.size(); g++)
{
cout << xorArray[g];
}
cout << "\n";
cout << "Key length is: " << keyReg.size();
cout << "\n";
for ( unsigned int i = 0; i < keyReg.size(); i++)
{
if (keyReg[i]==1)
{
count1++;
}
else {
count0++;
}
}
cout << "Number of 0's: " << count0 << "\n";
cout << "Number of 1's: " << count1 << "\n";
if ( keyReg.size()%2 ==0)
{
cout << "key length is even. \n";
if (count1==count0)
{
cout << "Key is perfect! \n";
}
else {
cout << "Key is not perfect! \n";
}
}
else
{
cout << "key length is odd. \n";
if ((count1==count0+1) || (count0==count1+1))
{
cout << "Key is perfect! \n";
}
else {
cout << "Key is not perfect! \n";
}
}
cin.get();
}
std::vector has an optimization for std::vector<bool>, and the size of a vector can be set at runtime.

C++ losing vector elements after .size()

I'm a C++ novice and my problem is that I somehow (seemingly) lose vector elements just by calling .size(). For the following code segment (full code attached below) I get the following output:
A: number of elements: 560
B: number of elements: 560
B: number of elements: 0
B: number of elements: 0
B: number of elements: 0
C: number of elements: 0
//SEGMENT IN QUESTION
cout << "A: number of elements: " << combinations.size() << endl;
float sum_vect[120][2];
for (int i = 0; i < combinations.size(); ++i) {
for (int j = 0; j < 2; ++j) {
sum_vect[i][j] = 0;
}
}
cout << "B: number of elements: " << combinations.size() << endl;
cout << "B: number of elements: " << combinations.size() << endl;
cout << "B: number of elements: " << combinations.size() << endl;
cout << "B: number of elements: " << combinations.size() << endl;
for (int i = 0; i < combinations.size(); ++i) {
combination = combinations.at(i);
for (int j = 0; j < order; ++j) {
sum_vect[i][0] += (float)virtual_pos[combination[j]][0];
sum_vect[i][1] += (float)virtual_pos[combination[j]][1];
}
}
vector<int> optimal_ind;
cout << "C: number of elements: " << combinations.size() << endl;
//AUXILIARY FUNCTIONS
void nchoosek_helper(int offset, int n, int k, vector<vector<int>> &combinations, vector<int> combination) {
if (k == 0) {
combinations.push_back(combination);
return;
}
for (int i = offset; i <= n - k; ++i) {
combination.push_back(i);
nchoosek_helper(i+1, n, k-1, combinations, combination);
combination.pop_back();
}
}
double euclidean_norm(double dist1, double dist2){
return sqrt(pow(dist1,2) + pow(dist2,2));
}
//FUNCTION IN QUESTION STARTS HERE
//weirdest: look at A B C
vector<vector<char> > step37::CUDADriver::get_access_pattern(int order){
vector<vector<char> > result;
vector<vector<int> > combinations;
vector<int> combination;
nchoosek_helper(0, 16 ,order, combinations, combination);
cout << "number of combinations: " << combination.size() << endl;
// //mapping lexical index 1-16 to 2D array
int virtual_pos [16][2];
for (int i = 0; i < 16; ++i) {
virtual_pos[i][0] = i%4 * order; //write x
virtual_pos[i][1] = (int)ceil(i/4) * order; //write y
cout << "mapping " << i << "to (" << i%4 * order << "'" << (int)ceil(i/4) * order<< ")" << endl;
}
cout << "A: number of elements: " << combinations.size() << endl;
float sum_vect[120][2];
for (int i = 0; i < combinations.size(); ++i) {
for (int j = 0; j < 2; ++j) {
sum_vect[i][j] = 0;
}
}
cout << "B: number of elements: " << combinations.size() << endl;
cout << "B: number of elements: " << combinations.size() << endl;
cout << "B: number of elements: " << combinations.size() << endl;
cout << "B: number of elements: " << combinations.size() << endl;
for (int i = 0; i < combinations.size(); ++i) {
combination = combinations.at(i);
for (int j = 0; j < order; ++j) {
sum_vect[i][0] += (float)virtual_pos[combination[j]][0];
sum_vect[i][1] += (float)virtual_pos[combination[j]][1];
}
}
vector<int> optimal_ind;
cout << "C: number of elements: " << combinations.size() << endl;
cout << "main loop"<< endl;
for (int i = order; i < order*2; ++i) {
for (int j = order; j < order*2; ++j) {
int pos [2];
// pos[0] = i;
// pos[1] = j;
pos[0] = j;
pos[1] = i;
cout << "current position: (" << j << "," << i << ")" << endl;
float min_len = std::numeric_limits<float>::infinity(); //minimum length of combined vector
float min_sum_ind = std::numeric_limits<float>::infinity(); //minimum sum of individual vectors
int min_idx = -1;
for (int k = 0; k < combinations.size(); ++k) {
int curr_vect [2];
curr_vect[0] = sum_vect[k][0] - pos[0] * order;
curr_vect[1] = sum_vect[k][1] - pos[1] * order;
float curr_len = euclidean_norm(curr_vect[0], curr_vect[1]);
float min_sum_tmp = 0;
combination = combinations[k];
for (int l = 0; l < order; ++l) {
min_sum_tmp += euclidean_norm(virtual_pos[combination.at(l)][0] - pos[0],
virtual_pos[combination.at(l)][1]- pos[1]);
}
if (i==4&&j==4){
cout << " ind sum: " << min_sum_tmp << " len: " << curr_len << " sv: (" << sum_vect[k][0] << "," << sum_vect[k][1] <<
") cv: (" << curr_vect[0] << "," << curr_vect[1] << ")" <<endl;
}
if (min_len > curr_len ||
min_len == curr_len && min_sum_tmp < min_sum_ind){
min_len = curr_len;
min_idx = k;
min_sum_ind = min_sum_tmp;
}
}
// cout <<
cout << "pushing minimal idx " << min_idx << endl;
optimal_ind.push_back(min_idx);
}
}
cout << "main loop done"<< endl;
//unpack optimal combinations into relative movements
vector<char> optimal_x((int)pow(order,3));
vector<char> optimal_y((int)pow(order,3));
cout << "number of elements: " << combinations.size() << endl;
for (int i = 0; i <(int)pow(order,2); ++i) {
cout << "optimal idx: " << optimal_ind.at(i) << endl;
combination = combinations.at(optimal_ind.at(i));
for (int j = 0; j < order; ++j) {
int lex_idx = combination.at(j); //some index between 0 and 15 from 4x4 grid
//mvt range in grid relative to thread position: -1 to +
int relative_x = -1 + lex_idx % 4;
int relative_y = -1 + (int) floor(lex_idx / 4);
optimal_x[i * order + j] = relative_x;
optimal_y[i * order + j] = relative_y;
}
}
//DEBUG print
for (int i = 0; i < (int)pow(order,2); ++i) {
combination = combinations.at(optimal_ind.at(i));
cout << "combination: " << i << " ";
for (int j = 0; j < order; ++j) {
cout << combination.at(j) << " ";
}
cout << endl;
}
result.push_back(optimal_x);
result.push_back(optimal_y);
for (int i = 0; i < optimal_x.size(); ++i) {
cout << (int)optimal_x.at(i) << " " << endl;
}
cout << "optimal sizes: " << optimal_x.size() << endl;
cout << "optimal sizes: " << optimal_y.size() << endl;
cout << "result size: " << result.size() << endl;
return result;
}
I really don't understand how it's possible for a function like .size() to change the vector object (or maybe it just happens coincidentally at the same time). The application runs in single thread but I guess it wouldn't matter anyways given that everything relevant should be contained within the scope of the function. Obviously, the code stops working at a later point when I actually try to access some elements of combinations (std::out_of_range). I guess I must be missing out on something very basic given the gravity of the error. What's disturbing is that everything works just fine if I use 2 as an argument to get_access_pattern(). Everything above (tested with 3 and 4) results in this error.
You have a buffer overrun. Your output:
A: number of elements: 560
Your code:
cout << "A: number of elements: " << combinations.size() << endl;
float sum_vect[120][2];
for (int i = 0; i < combinations.size(); ++i) {
for (int j = 0; j < 2; ++j) {
sum_vect[i][j] = 0;
}
}
Look at the "i" variable when it gets to 120 in that loop. You are accessing sum_vect[120][j], which is out-of-bounds.
When a buffer overrun occurs, your program then will exhibit undefined behavior.