2d vectors, seg fault

[miamidawgs]

I have this function that is supposed to take a 2d vector by reference and rotates it clockwise by 90 degrees. For some files I get a seg fault and for some the result is not correct.

void pgm_cw( vector <IVec> &p )
{
    vector <IVec> temp;     // temporary vector of vectors of ints
    int count = 0;        // count variable
    int count2 = 0;      // 2nd count variable

    temp.resize( p.size() );
    for( count = 0; count < p.size(); count++ )
    {
        temp[count].resize( p[count].size() );
        for( count2 = count; count2 < temp[count].size(); count2++ )
        {
            temp[count][count2] = p[count2][count];
        }
    }
    for( count = 0; count < temp.size(); count++ )
    {
        for( count2 = 0; count2 < temp[count].size(); count2++ )
        {
            temp[count][count2] = temp[count][p[count].size()-count2-1];    // set temp vector to p with 90 degree rotation
        }
    }
    p = temp;       // set p equal to temp
}

Can someone help me figure out whats wrong

[Peter87]

temp[count][count2] = p[count2][count];

This doesn't look right. I think it should be temp[count][count2] = p[count][count2];

[miamidawgs]

I got it. thanks for the help

[cire]

If the height and width of the original matrix are not equal, the height and width of the transposed matrix will not be equal to those of the original matrix.

#include <iomanip>
#include <iostream>
#include <vector>

using ivec = std::vector<int>;
using matrix = std::vector<ivec>;

matrix transpose(const matrix& m) {
    const auto m_rows = m.size();
    const auto m_cols = m.front().size();

    matrix result(m_cols, ivec(m_rows));

    for (std::size_t i = 0; i < m_rows; ++i)
        for (std::size_t j = 0; j < m_cols; ++j)
            result[j][i] = m[i][j];

    return result;
}

std::ostream& operator<<(std::ostream& os, const matrix& m) {

    for (std::size_t i = 0; i < m.size(); ++i) {
        for (std::size_t j = 0; j < m[i].size(); ++j)
            os << std::setw(5) << m[i][j];
        os << '\n';
    }

    return os;
}

int main() {
    matrix m = {
        { 1, 2, 3 },
        { 4, 5, 6 }
    };

    std::cout << m << '\n';
    std::cout << transpose(m) << '\n';
}