[英]Segmentation fault after using dynamic bitset in C++
我试图制作一个可变长度的线性反馈移位寄存器,所以我使用了动态位集而不是升压库中的位集。 编译该程序后,并在运行该程序时,它在显示xorArray的内容后立即产生了Segmentation错误。 我认为错误在于动态位集变量的定义,但我无法弄清楚。 有三个变量,inpSeq,operSeq和bit。 这是代码:
#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;
boost::dynamic_bitset<> inpSeq;
int polyLoc;
boost::dynamic_bitset<> operSeq;
boost::dynamic_bitset<> bit;
vector <int> xorArray;
vector <int> keyReg;
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];
cout << "bit 3 from prev: " << bit[seq_end] << "\n";
y = xorArray[r];
// cout << "opseq[y] is: " << operSeq[y] << "\n";
bit[seq_end] = bit[seq_end] ^ operSeq[y];
// cout << "bit[3] after xor: " << bit[seq_end] << "\n";
}
operSeq >>= 1;
// cout <<"operSeq after shift: " << operSeq << "\n";
operSeq[seq_end] = bit[seq_end];
// cout <<"opserSeq bit 4 after = bit[3]: " << operSeq[seq_end] << "\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();
}
一个问题是您在使用dynamic_bitsets之前未对其进行大小调整。 您应该调用dynamic_bitset::resize
。
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