C++ stringstream::fail方法代码示例

// Function to read the input data values
// Use is optional, but should be very helpful in parsing.  
bool Scene::readvals(stringstream &s, const int numvals, float *values) {
	for (int i = 0 ; i < numvals ; i++) {
		s >> values[i]; 
        if (s.fail()) {
			cout << "Failed reading value " << i << " will skip\n"; 
            return false;
        }
    }
    return true; 
}

// this statement is different than the get_alllabel becuase this just reads
// in a string, it does not not check for the inputted string's value
// the use of this occurs in the changeR and find commands
string get_label (stringstream &ss){
    string character;
    ss >> character;
    // this check tells us if an input was read
    if (ss.fail())
    {
        cout << "Error: missing argument" << endl;
        return "errrrrrrrrrrrrrrrrrrror";
    }
    return character; 
}

bool raytr::readvals(stringstream &s, const int numvals, double *values)
{
    for (int i = 0; i < numvals; ++i) {
        s >> values[i];
        if (s.fail()) {
            cerr << "Failed reading value " << i << " skips this line." << endl;
            return false;
        }
    }
    return true;
}

// this function was created to test if more then the desired amount of inputs
// were inputted
int get_extra (stringstream &ss){
    string i;
    ss >> i;
    //checks to see if it read an input
    if (!(ss.fail()))
    {
        cout << "Error: too many arguments" << endl;
        return 1;
    }
    return 0;
}

bool stringParse( stringstream &s, const int numvals, string* str )
{
    for( int i = 0; i < numvals; i++ )
    {
        s>>str[i];
        if (s.fail()) 
        {
            cout << "Failed reading value " << i << " will skip\n"; 
            return false;
        }
    }
}

bool ReadValues(stringstream & s, const int num, float * values)
{
	for(int i = 0; i < num; i++)
	{
		s >> values[i];
		if(s.fail())
		{
			cerr << "Failed Reading Values " << i << " Will Skip.\n";
			return false;
		}
	}
	return true;
}

// function for reading the resistance from the stringstream. While it reads the
// DOUBLE it tests 3 various errors that can arrive from the user
// I set an arbitrary return of -1 for an error occurrence so my function calls
// know if it failed, if not it returns the desired input 
double get_resistance (stringstream &ss){
    double i;
    ss >> i;
    // check for invalid number my making sure it was read, and also making sure
    // if the stored type into the variable matches and also checks to make sure 
    // the input is not a double or if a character follows the integer
    if ((ss.fail() && !(ss.eof()))){
        cout << "Error: argument is not a number" <<endl;
        return -1;
    }
    // checks to see if the resistance was negative
    else if (i < 0.0){
        cout << "Error: invalid resistance (negative)" << endl;
        return -1;
    }
    // this check tells us if an input was read
    else if (ss.fail())
    {
        cout << "Error: missing argument" << endl;
        return -1;
    }
    return i;
} 

bool treeTrace( stringstream &ss, vector<int> &T, int currSum )
{
	if( ss.rdbuf()->in_avail() == 0 )
		return false;
	char leftBracket;
	ss >> leftBracket;
	int integer;
	ss >> integer;
	bool leftTree;
	if( ss.fail() )
	{
		ss.clear();
		char otherBracket;
		ss >> otherBracket;
		return false;
	}

void ShapeArray::translate (stringstream& linestream) {
   string name;
   float xShift, yShift, xShape, yShape;
   
   linestream >> xShape >> yShape >> xShift >> yShift;
   if (linestream.fail()) {
      cout << "Error: invalid arguments\n";
      return;
   }
   
   Shape* shape = findShape (xShape, yShape);
   if (shape == NULL) {
      cout << "Error: could not find shape at (" << xShape << "," 
             << yShape << ")" << endl;
      return;
   }
   shape->setXcen (shape->getXcen() + xShift);
   shape->setYcen (shape->getYcen() + yShift);
   cout << "Success\n";
}

void ShapeArray::scale (stringstream& linestream) {
   string name;
   float scaleFac;
   
   linestream >> name >> scaleFac;
   if (linestream.fail()) {
      cout << "Error: invalid arguments\n";
      return;
   }
   
   if (scaleFac < 0) {
      cout << "Error: scaling factor must be nonnegative\n";
      return;
   }
   
   Shape* shape = findShape (name);
   if (shape == NULL) {
      cout << "Error: could not find shape with name " << name << endl;
      return;
   }   
   shape->scale (scaleFac);
   cout << "Success\n";
}