Problem reading from text file
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OK, actually this program works fine, but only when run from Visual Studio. However, when I click on the .exe or launch it from windows command prompt, I get an error: "Unhandled exception at 0x775e59c3 in Materials.exe: 0xC0000005: Access violation reading location 0x54a075d8" and Windows shuts the program down. The Requirement The program is to read from a text file a list of tabulated data of a given material: Temperature, Density, Viscosity... etc. For example: Temperature Density Viscosity ... ... 50 0.2 0.3 ... ... 100 0.25 0.33 ... ... The aim of the program is to read these values (several) of them, store to memory and do some sorts of interpolations. I created a structure, each holding the properties of the material at a given temperature. I then dynamically create an array of structures based on the number of data. If I had 100 readings, I create 100 arrays to structure. .h file
struct Material {
float temperature;
float density;
float viscosity;
};typedef Material* MATERIAL;
The above go into the header file .cpp file
MATERIAL* g_ptrMaterial; //global variable
void ReadFile (char* filePath)
{
vector<string> Tokens;
int i = 0;
string val;
char c;ifstream file(filePath); //instantiate and open file if (!file.fail()) { //cout << "Enter to begin..."; //cin >> c; //cout << "Reading from File ..."; g\_numberOfRows = getNumberOfRows(file); //gets number of readings g\_ptrMaterial = new MATERIAL\[g\_numberOfRows\]; getline(file, g\_fileHeader); //remove column headers i.e. Temperature, Density, etc while (getline(file, val)) { g\_ptrMaterial\[i\] = (MATERIAL) malloc(sizeof(MATERIAL)); Tokens = GetTokens(val); if (!Tokens.empty()) { //convertToFloat: converts string type to float type g\_ptrMaterial\[i\]->temperature = convertToFloat(Tokens.at(0)); g\_ptrMaterial\[i\]->density = convertToFloat(Tokens.at(1)); g\_ptrMaterial\[i\]->viscosity = convertToFloat(Tokens.at(2)); i++; } } } else { cerr << "FILE NOT FOUND!"; exit(1); }}
//separates the input line into column readings
vector<string > GetTokens (string val)
{
stringstream ss(val);
string temp;
vector<std::string > Tokens;while (ss >> temp) { Tokens.push\_back(temp); } return Tokens;}
Debugging What I di
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OK, actually this program works fine, but only when run from Visual Studio. However, when I click on the .exe or launch it from windows command prompt, I get an error: "Unhandled exception at 0x775e59c3 in Materials.exe: 0xC0000005: Access violation reading location 0x54a075d8" and Windows shuts the program down. The Requirement The program is to read from a text file a list of tabulated data of a given material: Temperature, Density, Viscosity... etc. For example: Temperature Density Viscosity ... ... 50 0.2 0.3 ... ... 100 0.25 0.33 ... ... The aim of the program is to read these values (several) of them, store to memory and do some sorts of interpolations. I created a structure, each holding the properties of the material at a given temperature. I then dynamically create an array of structures based on the number of data. If I had 100 readings, I create 100 arrays to structure. .h file
struct Material {
float temperature;
float density;
float viscosity;
};typedef Material* MATERIAL;
The above go into the header file .cpp file
MATERIAL* g_ptrMaterial; //global variable
void ReadFile (char* filePath)
{
vector<string> Tokens;
int i = 0;
string val;
char c;ifstream file(filePath); //instantiate and open file if (!file.fail()) { //cout << "Enter to begin..."; //cin >> c; //cout << "Reading from File ..."; g\_numberOfRows = getNumberOfRows(file); //gets number of readings g\_ptrMaterial = new MATERIAL\[g\_numberOfRows\]; getline(file, g\_fileHeader); //remove column headers i.e. Temperature, Density, etc while (getline(file, val)) { g\_ptrMaterial\[i\] = (MATERIAL) malloc(sizeof(MATERIAL)); Tokens = GetTokens(val); if (!Tokens.empty()) { //convertToFloat: converts string type to float type g\_ptrMaterial\[i\]->temperature = convertToFloat(Tokens.at(0)); g\_ptrMaterial\[i\]->density = convertToFloat(Tokens.at(1)); g\_ptrMaterial\[i\]->viscosity = convertToFloat(Tokens.at(2)); i++; } } } else { cerr << "FILE NOT FOUND!"; exit(1); }}
//separates the input line into column readings
vector<string > GetTokens (string val)
{
stringstream ss(val);
string temp;
vector<std::string > Tokens;while (ss >> temp) { Tokens.push\_back(temp); } return Tokens;}
Debugging What I di
I did not find anything blatantly wrong with your code. The only changes I made to get it to compile in my environment were to change
floattodoubleandconvertToFloat()toatof()."Old age is like a bank account. You withdraw later in life what you have deposited along the way." - Unknown
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
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OK, actually this program works fine, but only when run from Visual Studio. However, when I click on the .exe or launch it from windows command prompt, I get an error: "Unhandled exception at 0x775e59c3 in Materials.exe: 0xC0000005: Access violation reading location 0x54a075d8" and Windows shuts the program down. The Requirement The program is to read from a text file a list of tabulated data of a given material: Temperature, Density, Viscosity... etc. For example: Temperature Density Viscosity ... ... 50 0.2 0.3 ... ... 100 0.25 0.33 ... ... The aim of the program is to read these values (several) of them, store to memory and do some sorts of interpolations. I created a structure, each holding the properties of the material at a given temperature. I then dynamically create an array of structures based on the number of data. If I had 100 readings, I create 100 arrays to structure. .h file
struct Material {
float temperature;
float density;
float viscosity;
};typedef Material* MATERIAL;
The above go into the header file .cpp file
MATERIAL* g_ptrMaterial; //global variable
void ReadFile (char* filePath)
{
vector<string> Tokens;
int i = 0;
string val;
char c;ifstream file(filePath); //instantiate and open file if (!file.fail()) { //cout << "Enter to begin..."; //cin >> c; //cout << "Reading from File ..."; g\_numberOfRows = getNumberOfRows(file); //gets number of readings g\_ptrMaterial = new MATERIAL\[g\_numberOfRows\]; getline(file, g\_fileHeader); //remove column headers i.e. Temperature, Density, etc while (getline(file, val)) { g\_ptrMaterial\[i\] = (MATERIAL) malloc(sizeof(MATERIAL)); Tokens = GetTokens(val); if (!Tokens.empty()) { //convertToFloat: converts string type to float type g\_ptrMaterial\[i\]->temperature = convertToFloat(Tokens.at(0)); g\_ptrMaterial\[i\]->density = convertToFloat(Tokens.at(1)); g\_ptrMaterial\[i\]->viscosity = convertToFloat(Tokens.at(2)); i++; } } } else { cerr << "FILE NOT FOUND!"; exit(1); }}
//separates the input line into column readings
vector<string > GetTokens (string val)
{
stringstream ss(val);
string temp;
vector<std::string > Tokens;while (ss >> temp) { Tokens.push\_back(temp); } return Tokens;}
Debugging What I di
Is your application multi-threaded? This problem can occur in such application due to some conflicts between threads. When you single step through code, the conflict may not occur.
«_Superman_» I love work. It gives me something to do between weekends.
Microsoft MVP (Visual C++) -
Is your application multi-threaded? This problem can occur in such application due to some conflicts between threads. When you single step through code, the conflict may not occur.
«_Superman_» I love work. It gives me something to do between weekends.
Microsoft MVP (Visual C++)I didn't explicity create any extra threads, so I'll say it's single-threaded.
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OK, actually this program works fine, but only when run from Visual Studio. However, when I click on the .exe or launch it from windows command prompt, I get an error: "Unhandled exception at 0x775e59c3 in Materials.exe: 0xC0000005: Access violation reading location 0x54a075d8" and Windows shuts the program down. The Requirement The program is to read from a text file a list of tabulated data of a given material: Temperature, Density, Viscosity... etc. For example: Temperature Density Viscosity ... ... 50 0.2 0.3 ... ... 100 0.25 0.33 ... ... The aim of the program is to read these values (several) of them, store to memory and do some sorts of interpolations. I created a structure, each holding the properties of the material at a given temperature. I then dynamically create an array of structures based on the number of data. If I had 100 readings, I create 100 arrays to structure. .h file
struct Material {
float temperature;
float density;
float viscosity;
};typedef Material* MATERIAL;
The above go into the header file .cpp file
MATERIAL* g_ptrMaterial; //global variable
void ReadFile (char* filePath)
{
vector<string> Tokens;
int i = 0;
string val;
char c;ifstream file(filePath); //instantiate and open file if (!file.fail()) { //cout << "Enter to begin..."; //cin >> c; //cout << "Reading from File ..."; g\_numberOfRows = getNumberOfRows(file); //gets number of readings g\_ptrMaterial = new MATERIAL\[g\_numberOfRows\]; getline(file, g\_fileHeader); //remove column headers i.e. Temperature, Density, etc while (getline(file, val)) { g\_ptrMaterial\[i\] = (MATERIAL) malloc(sizeof(MATERIAL)); Tokens = GetTokens(val); if (!Tokens.empty()) { //convertToFloat: converts string type to float type g\_ptrMaterial\[i\]->temperature = convertToFloat(Tokens.at(0)); g\_ptrMaterial\[i\]->density = convertToFloat(Tokens.at(1)); g\_ptrMaterial\[i\]->viscosity = convertToFloat(Tokens.at(2)); i++; } } } else { cerr << "FILE NOT FOUND!"; exit(1); }}
//separates the input line into column readings
vector<string > GetTokens (string val)
{
stringstream ss(val);
string temp;
vector<std::string > Tokens;while (ss >> temp) { Tokens.push\_back(temp); } return Tokens;}
Debugging What I di
Exactly what does filepath contain? When running from Visual Studio, the current directory is the one containing the .sln and .vcproj files. If your filepath only contains the name ("myfile.txt"), then it must exist in that directory. When you run outside of visual studio, the current directory is the one containing the .exe file (normally the debug or release directory) and the file would then have to exist in that folder. It's best to specify a full path name ("c:\\mydocs\\mydata\\myfile.txt") to avoid these problems. Hope that helps.
Karl - WK5M PP-ASEL-IA (N43CS) PGP Key: 0xDB02E193 PGP Key Fingerprint: 8F06 5A2E 2735 892B 821C 871A 0411 94EA DB02 E193
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Exactly what does filepath contain? When running from Visual Studio, the current directory is the one containing the .sln and .vcproj files. If your filepath only contains the name ("myfile.txt"), then it must exist in that directory. When you run outside of visual studio, the current directory is the one containing the .exe file (normally the debug or release directory) and the file would then have to exist in that folder. It's best to specify a full path name ("c:\\mydocs\\mydata\\myfile.txt") to avoid these problems. Hope that helps.
Karl - WK5M PP-ASEL-IA (N43CS) PGP Key: 0xDB02E193 PGP Key Fingerprint: 8F06 5A2E 2735 892B 821C 871A 0411 94EA DB02 E193
Thanks Karl. The filePath is the absolute path to the text file I'm accessing. Accessing the file doesn't seem to give issues both in debug and release. A section of the code checks for file failure:
if(!file.fail())
{
//...
} -
Exactly what does filepath contain? When running from Visual Studio, the current directory is the one containing the .sln and .vcproj files. If your filepath only contains the name ("myfile.txt"), then it must exist in that directory. When you run outside of visual studio, the current directory is the one containing the .exe file (normally the debug or release directory) and the file would then have to exist in that folder. It's best to specify a full path name ("c:\\mydocs\\mydata\\myfile.txt") to avoid these problems. Hope that helps.
Karl - WK5M PP-ASEL-IA (N43CS) PGP Key: 0xDB02E193 PGP Key Fingerprint: 8F06 5A2E 2735 892B 821C 871A 0411 94EA DB02 E193
Good advice but I do not think that is the cause of the problem. If he was using
file(theifstreamobject) without first checking to see if it was valid (e.g., bad path), then an exception would be understandable."Old age is like a bank account. You withdraw later in life what you have deposited along the way." - Unknown
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
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Good advice but I do not think that is the cause of the problem. If he was using
file(theifstreamobject) without first checking to see if it was valid (e.g., bad path), then an exception would be understandable."Old age is like a bank account. You withdraw later in life what you have deposited along the way." - Unknown
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
Problem solved and in 3 ways! 1. The "Keep it Simple Stupid" Advice works! Instead of creating an array of MATERIAL i.e Material*, I simply created an array of Material, and accessed each Material by the . notation rather than the ->. i.e.
g_ptrMaterials = new Material [g_numberOfRows];
Material mat;
mat.temperature = 200.00; // for example2. One can stuff the structures into a vector:
vector vctr;
Material mat;
mat.temperature = 200.00; // for example
mat.density = bla bla;vctr.push_back(mat);
3. Lastly I modified the initial code. I don't know why it works ...
MATERIAL* arrMaterial = new MATERIAL[g_numberOfRows];
g_ptrMaterial = &arrMaterial[0];arrMaterial[i] = new Material; //everything works fine now
Perhaps the problem was mixing the malloc and new allocators? I suspected the problem was with the memory allocation, when the compiler continuously indicated errors in xmemory, dbgheap, and what not. It wasn't a v e r y pleasant experience. Anyway, I went for the first option, but one can go for any of the 3 options I suppose, without any harm. Thanks guys :)