I have one big problem with my NFA simulator.
When I run the code sometimes everything goes nice, but sometimes I get this
Process terminated with status -1073741819(0xC0000005)
What do I miss out and what to do to get this work fine?
This is the code:
#include <iostream>
#include<fstream>
#include<map>
using namespace std;
ifstream fin("fisier.txt");
class NFA {
int initiala,finale,stari,tran,cuvinte;
int *f;
multimap <pair <int,int>,char>t;
public:
void stari_finale();
void tranzitii();
void rezolvare();
};
void NFA::stari_finale()
{
fin>>finale;
f=new int[finale];
for(int i=1;i<=finale;i++)
fin>>f[i];
}
void NFA::tranzitii()
{
fin>>tran;
for(int i=1;i<=tran;i++)
{
int x,y;
char c2;
fin>>x>>y>>c2;
t.insert(make_pair(make_pair(x,y),c2));
}
}
void NFA::rezolvare()
{
fin>>stari>>initiala;
fin>>cuvinte;
for(int i=1;i<=cuvinte;i++)
{
int l;
fin>>l;
char *cuv=new char[l+1];
fin.get();
fin.getline(cuv,l+1);
int *c=new int[stari],nr=1;
c[1]=initiala;
for(int j=0;j<l;j++)
{
int *c1=new int[stari];
int n=0;
for(int k=1;k<=nr;k++)
for(int z=0;z<=stari;z++)
if(t.find(make_pair(c[k],z))!=t.end())
if(t.find(make_pair(c[k],z))->second==cuv[j])
n++,c1[n]=z;
for(int k=1;k<=n;k++)
c[k]=c1[k];
nr=n;
delete c1;
}
for(int j=1;j<=nr;j++)
{for(int k=1;k<=finale;k++)
if(c[j]==f[k])
{
cout<<"Word "<<cuv<<" is accepted!\n";
nr=-1;
break;
}
if(nr==-1)
break;
}
if(nr!=-1)
cout<<"Word "<<cuv<<" isn't accepted!\n";
delete c;
delete cuv;
}
}
int main()
{
NFA test;
test.stari_finale();
test.tranzitii();
test.rezolvare();
return 0;
}
One major problem is you are not calling the right delete on your variables. If you call new you need to call delete. If you call new[] you need to use delete[]. Mixing new[] and delete calls will cause undefined behavior which is a symptom of what is happening.
Your calls to delete for c, c1 and cuv should all be delete [] variable_name
You are writing outside the array here:
void NFA::stari_finale()
{
fin>>finale;
f=new int[finale];
for(int i=1;i<=finale;i++)
fin>>f[i];
}
f has the size finale, but i will be equal to finale in the last iteration.
Use this instead:
void NFA::stari_finale()
{
fin>>finale;
f=new int[finale];
for(int i=0;i<finale;i++)
fin>>f[i];
}
or, if you really need to use the 1-based indexing:
void NFA::stari_finale()
{
fin>>finale;
f=new int[finale + 1];
for(int i=1;i<=finale;i++)
fin>>f[i];
}
Related
I was trying to solve Reduce String on codechef which says
Give a string s of length l, and a set S of n sample string(s). We do reduce the string s using the set S by this way:
Wherever Si appears as a consecutive substring of the string s, you can delete (or not) it.
After each deletion, you will get a new string s by joining the part to the left and to the right of the deleted substring.
I wrote a recursive function as follows:-
Basically what i am doing in my code is either don't delete the character or delete it if it is part of any substring but it is giving wrong answer.
#include <bits/stdc++.h>
using namespace std;
#define mx 255
int dp[mx];
unordered_map<string,int> sol;
void init(int n)
{
for(int i=0;i<n;i++)
{
dp[i]=-1;
}
}
int solve(string str,int low,int high,vector<string> smp)
{
if(low>high)
{
return 0;
}
if(dp[low]!=-1)
{
return dp[low];
}
int ans=1+solve(str,low+1,high,smp);
for(int i=low;i<high;i++)
{
string tem=str.substr(low,i-low+1);
for(int j=0;j<smp.size();j++)
{
cout<<"low i high str"<<low<<" "<<i<<" "<<high<<" "<<smp[j]<<" "<<tem<<endl;
if(tem.compare(smp[j])==0)
{
ans=min(ans,solve(str,i+1,high,smp));
}
}
}
return dp[low]=ans;
}
signed main()
{
sol.clear();
string str;
vector<string> smp;
int n;
cin>>str;
cin>>n;
for(int i=0;i<n;i++)
{
string tem;
cin>>tem;
smp.push_back(tem);
}
int len=str.length();
init(len+1);
cout<<solve(str,0,len-1,smp)<<endl;
return 0;
}
PS:
link to the question
This question is toughest(seen so far) and most beautiful(again seen so far) question based on DP ON INTERVALS.
The initial code would definitely not work since it only considers single pass on the string and would not consider remaining string after deleting the patterns again and again.
There are 3 cases:-
Case 1 Either character is not deleted.
Case 2It is deleted as a part of contiguous substring.
Case 3It is deleted as a part of subsequence that matches any word given in the set of patterns and everything that is not part of that subsequence is deleted first as a substring(which again belongs to set of words).
The third part is the most tricky and requires enough thinking and is even tougher to implement too.
So for every substring we need to check whether this substring can be completely destroyed or not.
The function compute_full_recur() is the function that ensures that whether substring can be deleted either in Case 2 or Case 3.
The function compute_full takes care of Case 1.And finally this code will not run on codechef link since all the function are recursive with memoization but to verify the code is working i Have run it on Problem Reducto of Hackerrank which is exact similar with lower constraints.Download test cases and then run on test cases on your PC for verifying.
#include <iostream>
#include <vector>
#include <string>
using namespace std;
#define mx 252
#define nx 40
bool full[mx][mx],vis[mx][mx],full_recur[mx][mx][nx][nx];
int ans[mx];
void init()
{
for(int i=0;i<mx;i++)
{
for(int j=0;j<mx;j++)
{
full[i][j]=false,vis[i][j]=false;
}
}
for(int i=0;i<mx;i++)
{
ans[i]=-1;
}
for(int i=0;i<mx;i++)
{
for(int j=0;j<mx;j++)
{
for(int k=0;k<nx;k++)
{
for(int l=0;l<nx;l++)
{
full_recur[i][j][k][l]=false;
}
}
}
}
}
bool compute_full_recur(string str,int low,int high,vector<string> pat,int idx,int len)
{
if(low>high&&len==pat[idx].length())
{
return true;
}
if(low>high&&len<pat[idx].length())
{
full_recur[low][high][idx][len]=false;
return false;
}
if(str[low]==pat[idx][len]&&compute_full_recur(str,low+1,high,pat,idx,len+1))
{
return full_recur[low][high][idx][len]=true;
}
for(int i=low+1;i<=high;i++)
{
if(str[low]==pat[idx][len]&&full[low+1][i]&&compute_full_recur(str,i+1,high,pat,idx,len+1))
{
return full_recur[low][high][idx][len]=true;
}
}
full_recur[low][high][idx][len]=false;
return false;
}
void compute_full(string str,int low,int high,vector<string> pats)
{
if(low>high)
{
return;
}
if(vis[low][high])
{
return;
}
vis[low][high]=true;
compute_full(str,low+1,high,pats);
compute_full(str,low,high-1,pats);
for(int i=0;i<pats.size();i++)
{
if(!full[low][high])
full[low][high]=compute_full_recur(str,low,high,pats,i,0);
}
}
int compute_ans(string str,int low,int high)
{
if(low>high)
{
return 0;
}
if(ans[low]!=-1)
{
return ans[low];
}
int sol=1+compute_ans(str,low+1,high);
for(int i=low+1;i<=high;i++)
{
if(full[low][i]==true)
{
sol=min(sol,compute_ans(str,i+1,high));
}
}
return ans[low]=sol;
}
signed main()
{
int t;
cin>>t;
while(t--)
{
string str;
int n;
vector<string> pats;
cin>>n>>str;
for(int i=0;i<n;i++)
{
string tem;
cin>>tem;
pats.push_back(tem);
}
init();
compute_full(str,0,str.length()-1,pats);
cout<<compute_ans(str,0,str.length()-1)<<endl;
}
return 0;
}
I have written code for reading a text file containing 37000 DNA sequences and analyzing the sequences for specific pattern . But every time I run the code it says
codon.exe stopped working and Process returned 255 (0xff)
This is the code :
#include<iostream>
#include<vector>
#include<cstring>
#include<cstdio>
#include<fstream>
using namespace std;
int main()
{
ifstream dnafile;
dnafile.open("code.txt"); /// code.txt is notepad file name
if(!dnafile.is_open())
{
cout<<"file not opened";
}
int c=0;
vector <int> a;
vector <char> codon;
int l=0; /// lTH TERM OF DNA SEQUENCE
char x;
while((x = dnafile.get()) != EOF) /// READING CHARACTER BY CHARACER FROM FILE
{
if(x=='>')
{
l=0;
codon.push_back('#');
continue;
}
l++;
codon.push_back(x);
}
for(int l=0;l<codon.size();l++)
{
if(codon.at(l)=='#')
c++;
}
int c1[c+1];
float b[c+1],d[c+1];
for(int j=0;j<(c+1);j++)
{
for(int i=1;i<a.size();i++)
{
if (a[i]==0&&c1[j]!=0)
{
d[j]=(b[j]+a[i-c1[j]])/c1[j];
i++;
break;
}
else if(c1[j]==0)
d[j]=0;
else
{
b[j]=b[j]+(a[i]-a[i-1]);
}
}
continue;
}
for(int j=0,i=0;j<a.size(),i<(c+1);j=j+c1[i],i++)
{
cout<<"("<<d[i]<<","<<c1[i]<<","<<a[j]<<")"<<", ";
}
return 0;
}
Updated Code
Well I found two mistakes in it that you're making here and that's variable length array. You'd be getting an error on
int c1[c+1];
float b[c+1],d[c+1];
Update it to be a dynamic array like this, since c is a variable and is assigned a value at RunTime.
It'll only work if c is a const. For a variable you'd get C++ forbids variable length array
int *c1 = new int[c+1];
float *b = new float[c+1], *d = new float[c+1];
and don't forget to deallocate the memory in the end
delete [] c1;
delete [] b;
delete [] d;
Or you can use STL library as a workaround.
vector<int> or vector<float> would also work since they can update their size as you push elements into them
Also where you are checking your file existence
if(!dnafile.is_open())
{
cout<<"file not opened";
}
Add an else statement like this, since the code afterwards runs (in your implementation) even if the file is not found after printing "file not found"
else {
int c=0;
// all the code
delete [] c1;
delete [] b;
delete [] d;
}
return 0;
The following program builds perfectly. However, during execution, no matter what value of degree I provide, the program takes only 2 array elements as input. I suppose there might be a problem with the redeclaration of the arrays f[] and fDash[]. In JAVA, arrays can be easily redeclared using the new keyword. Is that possible in c++ too? If not, what is the alternative?
P.S. I am using CodeBlocks 13.12 and compiler settings are standard.
#include <iostream>
#include <cmath>
using namespace std;
class Polynomial
{
public:
void input(void);
void expression(void);
void derivative(void);
double value(double var);
double der(double var);
private:
int f[];
int fDash[];
int degree;
};
void Polynomial::input()
{
cout<<"Enter degree of polynomial:\t";
cin>>degree;
f[degree+1];
fDash[degree];
for(int i=0;i<=degree;i++)
{
cout<<"Enter coefficient of x^"<<i<<":\t";
cin>>f[i];
}
for(int i=0;i<degree;i++)
{
fDash[i]=f[i+1]*(i+1);
}
}
void Polynomial::expression()
{
cout<<f[0];
for(int i=1;i<=degree;i++)
{
cout<<" + "<<f[i]<<"*x^"<<i;
}
}
void Polynomial::derivative()
{
cout<<fDash[0];
for(int i=1;i<degree;i++)
{
cout<<" + "<<fDash[i]<<"*x^"<<i;
}
}
double Polynomial::value(double var)
{
double val=0.0;
for(int i=0;i<=degree;i++)
{
val+=f[i]*pow(var,i);
}
return val;
}
double Polynomial::der(double var)
{
double val=0.0;
for(int i=0;i<degree;i++)
{
val+=fDash[i]*pow(var,i);
}
return val;
}
int main()
{
double lb,ub,step,var,accum=0.0,rms;
int counter=0;
Polynomial p;
p.input();
cout<<"\n\n\nPolynomial is:\nf(x) = ";
p.expression();
cout<<"\n\n\nDerivative is:\nf'(x) = ";
p.derivative();
cout<<"\n\n\nEnter x0,x1,Step:\t";
cin>>lb;
cin>>ub;
cin>>step;
cout<<"\n\n\n====================================";
cout<<"\n\nx\t|\tf\t|\tf'\n\n\n";
var=lb;
while(var<=ub)
{
cout<<var<<"\t|\t"<<p.value(var)<<"\t|\t"<<p.der(var)<<"\n";
accum+=pow(p.value(var),2.0);
var+=step;
counter++;
}
cout<<"\n====================================";
accum/=counter;
rms=sqrt(accum);
cout<<"\nRMS energy of f(x) = "<<rms;
return 0;
}
This does not compile on clang, it fails with "error: field has incomplete type 'int []' int f[];" and likewise for fDash.
Let's see how you declared these fields:
int f[];
int fDash[];
In C++, you can declare arrays with statically defined sizes like so:
int f[5];
int fDash[6];
If you want dynamic arrays, which you need in this case, you'd have to declare
int* f;
int* fDash;
and allocate memory for them with
f = new int[5];
You also must release that memory somewhere like so
delete [] f;
But beware - managing your own memory like this is error prone and should be avoided. You should just use std::vector instead, which is the equivalent of java.util.ArrayList:
std::vector<int> f;
std::vector<int> fDash;
And modify your input function like so:
void Polynomial::input()
{
cout<<"Enter degree of polynomial:\t";
cin>>degree;
int input;
for(int i=0;i<=degree;i++)
{
cout<<"Enter coefficient of x^"<<i<<":\t";
cin>>input;
f.push_back(input);
}
for(int i=0;i<degree;i++)
{
fDash.push_back(f[i+1]*(i+1));
}
}
You don't use arrays correctly. You need to allocate memory if you want to use array of variable length. How use arrays in c++ see this and this, or use std::vector
I'm trying to create an application in C++. In the application I have the default constructor and another constructor with 3 arguments.
The user is providing from the keyboard an integer that it will be used to create an array of objects using the non default constructor.
Unfortunately I haven't been able to finish it till now, since I'm having issues with the creation of the array of objects that they will use the non default constructor.
Any suggestions or help?
#include<iostream>
#include<cstring>
#include<cstdlib>
#include <sstream>
using namespace std;
class Station{
public:
Station();
Station(int c, char *ad, float a[]);
~Station();
void setAddress(char * addr){
char* a;
a = (char *)(malloc(sizeof(addr+1)));
strcpy(a,addr);
this->address = a;
}
void setCode(int c){
code=c;
}
char getAddress(){
return *address;
}
int getCode(){
return code;
}
float getTotalAmount(){
float totalAmount=0;
for(int i=0;i<4;i++){
totalAmount+=amount[i];
}
return totalAmount;
}
void print(){
cout<<"Code:"<<code<<endl;
cout<<"Address:"<<address<<endl;
cout<<"Total Amount:"<<getTotalAmount()<<endl;
cout<<endl;
}
private:
int code;
char *address;
float amount[4];
};
Station::Station(){
code= 1;
setAddress("NO ADDRESS GIVEN");
amount[0]= 0.0;
amount[1]= 0.0;
amount[2]= 0.0;
amount[3]= 0.0;
}
Station::Station(int c, char *ad, float a[]){
if( (c>=1&& c<=10 ) ){
code=c;
address=ad;
for(int i=0;i<4;i++){
amount[i]=a[i];
}
}else{
code= 1;
setAddress("NO ADDRESS GIVEN");
amount[0]= 0.0;
amount[1]= 0.0;
amount[2]= 0.0;
amount[3]= 0.0;
}
}
Station::~Station(){
}
int main(){
int size,code;
char *addrr;
addrr = (char *)(malloc(sizeof(addrr+1)));
float mes[4];
do{
cout<<"size of array:";
cin>>size;
}while(size<=0 || size>=11);
// Station *stations= new Station[size];
// Station** stations = new Station*[size];
Station stations[size];
for(int i=0;i<size;i++){
cout<<"code:";
cin>>code;
cout<<"address:";
cin>>addrr;
double amo=0;
for(int k=0;k<4;k++){
cout<<"values"<<k+1<<":";
cin>>mes[k];
}
}
/*
for(int q=0;q<size;q++){
stations[q].print();
}
*/
return 0;
}
the values that I'll take from cin I want to assign them to the objects of the array!
You can either create the array default-initialized and then fill the array with the wanted object:
foo arr[10];
std::fill(arr, arr+10, foo(some, params));
Alternatively you could use std::vector and do just:
std::vector<foo> arr(10, foo(some, params));
In C++0x, you can use braced-init-list in new expression, which means you can do this:
#include <iostream>
class A
{
public:
A(int i, int j){std::cout<<i<<" "<<j<<'\n';}
};
int main(int argc, char ** argv)
{
int *n = new int[3]{1,2,3};
A *a = new A[3]{{1,2},{3,4},{5,6}};
delete[] a;
delete[] n;
return 0;
}
Compiled under g++ 4.5.2, using g++ -Wall -std=c++0x -pedantic
Since you say you can't use std::string, this is going to be much more difficult. The line addrr = (char *)(malloc(sizeof(addrr+1))); is not doing what you think it is. Instead of using malloc to allocate on the heap and since there is no free (which will lead to a memory leak), it will be much easier if we allocate on the stack with a predetermined buffer size: char addrr[BUFFER_LENGTH]. With BUFFER_LENGTH defined before Station's declaration as const int BUFFER_LENGTH = 20; or some other appropriate length.
To use the non-default constructor, adding stations[i] = Station(c, addrr, mes); at the end of the for loop will do the trick.
for(int i=0;i<size;i++){
cout<<"code:";
cin>>code;
cout<<"address:";
cin>>addrr; // do not read in strings longer than 20 characters or increase BUFFER_LENGTH’s size
double amo=0;
for(int k=0;k<4;k++){
cout<<"values"<<k+1<<":";
cin>>mes[k];
}
stations[i] = Station(c, addrr, mes);
}
But, this is not going to work properly since the constructor is copying the addrr pointer, not the data. I would recommend also changing the data member char *address to char address[BUFFER_LENGTH]. Then, in the constructor you can replace the line address=ad; with strcpy(address, ad);.
Note: setAddress and getAddress will now need to be updated.
Another line that is troubling is Station stations[size];. This is non-standard since size is not a known at compile time. Either use Station *stations= new Station[size]; and remember to delete or if you can use a std::vector, use std::vector<Station> stations(size);
If you do go the std::vector route, using push_back will work nicely:
std::vector<Station> stations;
for(int i=0;i<size;i++){
cout<<"code:";
cin>>code;
cout<<"address:";
cin>>addrr;
double amo=0;
for(int k=0;k<4;k++){
cout<<"values"<<k+1<<":";
cin>>mes[k];
}
stations.push_back( Station(c, addrr, mes) );
}
Hello i'm trying to program the addition of 2 matrices into a new one (and it does when i run the program step by step) but for some reason VS 2010 gives me an access error after it does the addition.
Here is the code.
#include <iostream>
#include <cstdio>
#include <conio>
using namespace std;
class operatii
{
typedef double mat[5][5];
mat ms,m1,m2;
int x1,x2,y1,y2;
public:
void preg();
int cit_val();
void cit_mat(int&,int&,double[5][5]);
void suma();
void afisare(int&,int&,double[5][5]);
};
void operatii::preg()
{
cit_mat(x1,y1,m1);
cit_mat(x2,y2,m2);
suma();
afisare(x1,y1,ms);
}
int operatii::cit_val()
{
int n;
cin>>n;
return n;
}
void operatii::cit_mat(int& x,int& y,double m[5][5])
{
char r;
cout<<"Matrice patratica? Y/N ";
cin>>r;
if ((r=='y')||(r=='Y'))
{
cout<<"Numar linii si coloane: ";
x=cit_val();
y=x;
}
else
{
cout<<"Numar linii: ";
x=cit_val();
cout<<"Numar coloane: ";
y=cit_val();
}
for (int i=1;i<=x;i++)
for (int j=1;j<=y;j++)
cin>>m[i][j];
}
void operatii::suma()
{
if ((x1==x2)&&(y1==y2))
for (int i=1;i<=x1;i++)
for (int j=1;i<=y1;j++)
ms[i][j]=m1[i][j]+m2[i][j];
else cout<<"Eroare";
}
void operatii::afisare(int& x,int& y,double m[5][5])
{
cout<<endl;
for (int i=1;i<=x;i++)
{
for (int j=1;j<=y;j++)
cout<<m[i][j];
cout<<endl;
}
}
void main()
{
operatii matrice;
matrice.preg();
system("PAUSE");
}
Any kind of help would be apreciated.
Arrays are 0-based in c++.
Change your various variants of for (somevar=1; somevar<=something) to for (somevar=0; somevar<something)
You're writing past the end of your arrays, which overwrites stack return address, leading to a return to nonexecutable code, again leading to an access violation.
Also,
for (int j=1;i<=y1;j++)
I think you want to use j not i here. Such errors are much easier to see if you use longer and more distinct variable names than "i" and "j", such as e.g. "Line" and "Column"