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Vector and map throw exception

Tags:

c++

c++11

my task is output all ten-digit numbers, where the numbers don't repeat. And I first I am using something like this:

#include <cstdio>
#include <iostream>
#include <string>
#include <map>
#include <functional>

using namespace std;

void Task5() {
    auto initialization = [](map<int, bool> *m, int count) {
        for (int i = 0; i < 10; ++i)
            m[i] = true;
    };
 /*For cut duplicate number in map*/
    auto cutting = [](map<int, bool> *m, int count, int value) {
        for (int i = 9; i > count; --i)
            m[count][i][value] = false;
    };
 /*For create copy map*/
    auto mould = [](map<int,bool> *m, map<int, bool> *m_copy, int count) -> map<int, bool>* {
        if (m_copy == nullptr) {
            map<int, bool> *m_copy = new map<int, bool>[10 - count];
            for (int i = 9; i > count; --i)
                for (int j = 0; j < 10; ++j)
                    m_copy[i][j] = m[i][j]; /*<= here throw exepition*/
            return m_copy;
        }
        else {
            for (int i = 9; i > count; --i)
                for (int j = 0; j < 10; ++j)
                    m[i][j] = m_copy[i][j];
            return m;
        }
    };

    function<void(map<int, bool>*, int, int*)> recursive;
    recursive = [mould, cutting, &recursive](map<int, bool> *m, int count = 1, int *result = nullptr) -> void {
        if (count != 10) {
            for (int i = 0; i < 10; ++i) {
                static map<int, bool> *m_copy;
                if (i == 0)
                    m_copy = mould(m, nullptr, 1);
                else {
                    m = mould(m, m_copy, 1);
                    if (m[count][i])
                        result[count - 1] = i;
                    else
                        continue;
                }       
                cutting(m, count, i);
                recursive(m, ++count, result);
            }
            delete[] m_copy;
        }
        else {
            for (int i = 0; i < 10; ++i)
                cout << result[i];
            cout << endl;
        }
    };
     /*Create map
       int is digit(can be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9)
       if digit is used bool will be false*/
    map<int, bool> *m = new map<int, bool>[10];
    for (int i = 0; i > 10; ++i)
        initialization(m, i);
    m[0][0] = false; //First number cant' be 0
    int *result = new int[10];
    recursive(m, 1, result);
    delete[] m;
    delete[] result;
}

int main(){
    Task5();
    return 0;
}

But it throw exepition std::out_of_range. Now I had look and map[0] have size 1, other map(map[1], map[2] and other) have size 0. Why it is? So I look to forum and can't find answer. So I I decided to rewrite solution. And write something like this:

#include <cstdio>
#include <iostream>
#include <string>
#include <map>
#include <functional>
#include <vector>

using namespace std;

auto end_task = []() {
    cout << endl << endl << endl;
};

void initialization(vector<bool> &vec) {
    vec.reserve(10);
    for (int i = 0; i < 10; ++i)
        vec[i] = true;
}

void cutting(vector<bool> *vec, int count, int value) {
    for (int i = 9; i > count; --i)
        vec[i][value] = false;
}

vector<bool> *mould(vector<bool> *vec, vector<bool> *vec_copy, int count) {
    if (vec_copy == nullptr) {
        vector<bool> *vec_copy = new vector<bool>[10 - count];
        for (int i = 9; i > count; --i)
            for (int j = 0; j < 10; ++j)
                vec_copy[i][j] = vec[i][j];
        return vec_copy;
    }
    else {
        for (int i = 9; i > count; --i)
            for (int j = 0; j < 10; ++j)
                vec[i][j] = vec_copy[i][j];
        return vec;
    }
}

void recursive(vector<bool> *vec, int count = 1, int *result = nullptr) {
    if (count != 10) {
        for (int i = 0; i < 10; ++i) {
            static vector<bool> *vec_copy;
            if (i == 0)
                vec_copy = mould(vec, nullptr, 1);
            else {
                vec = mould(vec, vec_copy, 1);
                if (vec[count][i])
                    result[count - 1] = i;
                else
                    continue;
            }
            cutting(vec, count, i);
            recursive(vec, ++count, result);
        }
        delete[] vec_copy;
    }
    else {
        for (int i = 0; i < 10; ++i)
            cout << result[i];
        cout << endl;
    }
}

void Task5() {
    vector<bool> *vec = new vector<bool>[10];
    for (int i = 0; i > 10; ++i)
        initialization(vec[i]);
    vec[0][0] = false;
    int *result = new int[10];
    recursive(vec, 1, result);
    delete[] m;
    delete[] result;
    end_task();
}


int main(){
    Task5();
    return 0;
}

(Whithout lambda function because I began to suspect them)But here vector size is 1 and 0. And I have error: Vector iterator not dereferencable. Why? Where my mistake?

like image 886
emik_g Avatar asked Feb 01 '26 23:02

emik_g


2 Answers

An easy way to solve your issue with STL is to use std::next_permutation:

std::vector<int> digits{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}; // Sorted

do
{
    for (auto d : digits) {
        std::cout << d;
    }
    std::cout << std::endl;
} while (std::next_permutation(digits.begin(), digits.end()));

Demo

like image 55
Jarod42 Avatar answered Feb 03 '26 12:02

Jarod42


Lets take a closer look a the line where you get the exception (together with some context):

map<int, bool> *m_copy = new map<int, bool>[10 - count];
for (int i = 9; i > count; --i)
    for (int j = 0; j < 10; ++j)
        m_copy[i][j] = m[i][j]; /*<= here throw exepition*/

The first line create a brand new variable named m_copy (adding to the confusion since it hides the lambda argument by the same name) and makes it point to an "array" of 10 - count elements.

The top-index of that "array" will be 10 - count - 1, which will only be equal to 9 if count == 0. That means the outer loop will start with an invalid and out of bounds index anytime that count > 0.

like image 41
Some programmer dude Avatar answered Feb 03 '26 12:02

Some programmer dude



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