Question

I’m trying to generate all possible subsets for a specific bool vector of size 3. So there should be 8 possible subsets:

#include<iostream>
#include<fstream>
#include<string>
#include<stdio.h>
#include<stdlib.h>
#include<vector>

using namespace std;
int n = 3;
int mis(vector<bool> f,int i){
        for(int j=0; j <f.size();j++)
            cout<<f[i]<<" ";
        cout<<endl; 
        f[i] = false;
        return mis(f,i+1);
        f[i] = true;
        return mis(f,i+1);
}

int main(){
    vector<bool> f;
    f.resize(n);
    int m = mis(f,0);
}

I’m getting the following error:

a.out: malloc.c:3096: sYSMALLOc: Assertion `(old_top == (((mbinptr) (((char *) &((av)->bins[((1) - 1) * 2])) - __builtin_offsetof (struct malloc_chunk, fd)))) && old_size == 0) || ((unsigned long) (old_size) >= (unsigned long)((((__builtin_offsetof (struct malloc_chunk, fd_nextsize))+((2 * (sizeof(size_t))) - 1)) & ~((2 * (sizeof(size_t))) - 1))) && ((old_top)->size & 0x1) && ((unsigned long)old_end & pagemask) == 0)' failed.
Aborted

Answer 1

In fact you did several mistakes. Here the right code:

#include<iostream>
#include<fstream>
#include<string>
#include<stdio.h>
#include<stdlib.h>
#include<vector>

using namespace std;

int n = 3;

int mis(vector<bool> f, int i)
{
    if (i > n)
    {
        return 0;
    }
    else if (i == n)
    {
        for(int j = 0; j < n; j += 1)
        {
            cout << f[j] << " ";
        }
        cout << endl;
        return 1;
    }

    f[i] = false;
    int a = mis(f, i + 1);

    f[i] = true;
    int b = mis(f, i + 1);

    return a + b;
}

int main()
{
    vector<bool> f(n);
    int m = mis(f, 0);

    cout << "Total: " << m << endl;
}

1. In the loop that prints the content of vector you use variable j but prints f[i]. I believe this is the reason of assertion you got.

2. The code f[i] = true; return mis(f, i + 1); is not reachable. You should use variables to remember the intermediate result as did I.

3. There is no exit from your recursion. You never check whether i is too big.