Access Violation Writing Array Reading .

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Access Violation Writing Array Reading .

Access Violation Writing Array Reading .txt

Dear all,

I'm a newbie in any programming, and recently must work on c++. I have a difficulty in forming an array and reading a file at the same time. I have tried the code, but I couldn't understand why it is not working (access violation error). Appreciating any advise. Thank you..

[input .txt]
Knt
1 1 0 1000 1000 1000
[input .txt]


#include <fstream>
#include <iostream>

using namespace std;

class sce{
 public:
 double getK(int nN, int nT) { return K[nN][nT]; }
	void setK(int nN, int nT, double newK) { K[nN][nT] = newK; }

 void initK(int nC, int nN, int nT){
   //...another function with int nC
   K = new double*[nN];
   for (int n = 0; n < nN; n++) {
	K[n] = new double[nT];
		}
 }
 ~sce(){};
 private:
 double** K;
};

int main(){
 int n, a, b;
 int temp;
 double tempDouble;
 char tempChar;
 ifstream file; 	
 string line;
 string filename = "data\\data" + to_string(dset) + ".txt";
	
 file.open(filename.c_str());
 if (file.is_open()) {
	cout << "Can open file!" <<endl;}
 else { cout << "Can not open file!" << endl;
	exit(1);}
 
 std::getline(file, line);
 file >> temp; gen.setnN(temp); //calling the gen class
 file >> temp; gen.setnC(temp);
 file >> temp; gen.setnT(temp);
 file >> temp; gen.setnS(temp);
 sce = new SCE[gen.getnS()];

 for (s = 0; s < nS; s++) {
      sce[s].initsce(nC, nN, nT);}
 int ni = nN * nS;
 
  //get K
 file >> tempChar; getline(file, line);
 for (int i = 0; i < ni; i++) {
    file >> a;
    file >> b; 
    for (t = 0; t < nT; t++) {
        file >> tempDouble; 
        sce[a].setK(b, t, tempDouble);	
    }
 }

 return();
};

TheIdeasMan (6817)

12:17: warning: unused parameter 'nC' [-Wunused-parameter]
In function 'int main()': 31:45: error: 'dset' was not declared in this scope 40:16: error: 'gen' was not declared in this scope 44:6: error: expected unqualified-id before '=' token 46:7: error: 's' was not declared in this scope 46:18: error: 'nS' was not declared in this scope 47:10: error: expected unqualified-id before '[' token 48:11: error: 'nN' was not declared in this scope 48:16: error: 'nS' was not declared in this scope 55:10: error: 't' was not declared in this scope 55:21: error: 'nT' was not declared in this scope 57:12: error: expected unqualified-id before '[' token 61:9: error: expected primary-expression before ')' token 25:6: warning: unused variable 'n' [-Wunused-variable] At global scope: 62:2: warning: extra ';' [-Wpedantic]

Best advice is to use a std::vector and not arrays, and don't do manual memory management. Try to avoid using pointers.

Try to write that is easy to read, choose good variable and function names.

Always initialise your variables. Read the manual.

Must have an object of the class type, before one can call the class functions

jonnin (11441)

check the obvious pointer problems or get rid of the pointers.
.. is the outer dimension correct in your debugger?
the inner dimension?
the loop iterations, are they also the expected bounds?

is there a reason for the pointers here? Would a vector work?
line 48 looks funky to me.
you say ni is nn*ns but you allocated (init function) with nn
its a little hard to follow the variable names....

Last edited on

ppkaa (2)

Dear Jonnin and TheIdeasMan,

Thank you for the advise. I will reprocess the array with CPLEX but let me try to initiate it with vector, as well as find better way to revise line 48. Thank you

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Access Violation Writing Array Reading .txt