problemer med cout

[jj_]

Prøver å skrive ut en string med cout, men får feilmeldingen:

error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'std::string' (or there is no acceptable conversion)

på denne linja:

 

cout << sDisplay;

 

Jeg karer ikke å finne hva som er feil, er det noen som kan hjelpe meg?

Bruker Visual Studio Express 2008. Resten av koden er som følger (linja med feil er nest nederste linje):

 

// DateIO.cpp
//
// Program to recieve, validate and display a date.
//
// Original Code: M.Mason
// Modified by: <<insert your name here >>
//

#include <iostream>
#include <iomanip>

using namespace std;

// Function Prototypes
bool GetDate(int &nDay, int &nMonth, int &nYear);
bool ValidDate(int nDay, int nMonth, int nYear);
bool DisplayDate(int nDay, int nMonth, int nYear);

// Main
int main(int argc, char *argv[]){
 int nFirstDay;
 int nFirstMonth;
 int nFirstYear;

 do {
  GetDate(nFirstDay, nFirstMonth, nFirstYear);
 } while ( !ValidDate(nFirstDay, nFirstMonth, nFirstYear) );

 DisplayDate(nFirstDay, nFirstMonth, nFirstYear);

 return 0;
}

// Function implementations ...

// bool GetDate(int &nDay, int &nMonth, int &nYear)
// prompts user for the day, the month and the year (seperately)
// checks to see that it got numbers.  
bool GetDate(int &nDay, int &nMonth, int &nYear){
do{	
	if (cin.fail()){
		cin.clear();
		while (cin.get() != '\n');
		cout << "An error occured: Expected integers" << '\n';
	}

	cout << "Enter date (dd mm yyyy): ";
	cin >> nDay >> nMonth >> nYear;
} while (!cin.good());

 return true;
}


// bool ValidDate(int nDay, int nMonth, int nYear)
// Checks the values of nDay, nMonth and nYear to see if they form a valid date.
// returns false if the year is invalid.
bool ValidDate(int nDay, int nMonth, int nYear){
string sDay = "" + nDay;
string sMonth = "" + nMonth;
string sYear = "" + nYear;
bool bErr = false;

if (nDay < 1 || nDay > 31) bErr = true;
if (nMonth < 1 || nMonth > 12) bErr = true;
if (nYear < 1900 || nYear > 2008) bErr = true;

if (bErr){
	cout << "\nError in date format, please try again\n";
	return false;
} else {
	return true;
}
}

// bool DisplayDate(int nDay, int nMonth, int nYear)
// Writes the date out tot he cout stream in DD/MM/YYYY format
bool DisplayDate(int nDay, int nMonth, int nYear){
string sDisplay;

enum months{
	jan = 1,
	feb, mar, apr, may, jun, jul,
	aug, sep, oct, nov, dec};

switch (nMonth){
	case jan:
		sDisplay = "January ";
		break;
	case feb:
		sDisplay = "February ";
		break;
	case mar:
		sDisplay = "March ";
		break;
	case apr:
		sDisplay = "April ";
		break;
	case may:
		sDisplay = "May ";
		break;
	case jun:
		sDisplay = "June ";
		break;
	case jul:
		sDisplay = "July ";
		break;
	case aug:
		sDisplay = "August ";
		break;
	case sep:
		sDisplay = "September ";
		break;
	case oct:
		sDisplay = "October ";
		break;
	case nov:
		sDisplay = "November ";
		break;
	case dec:
		sDisplay = "December ";
		break;
}

if (nDay == 1){
	sDisplay += nDay + "st ";
} else if (nDay == 2){
	sDisplay += nDay + "nd ";
} else if (nDay == 3){
	sDisplay += nDay + "rd ";
} else {
	sDisplay += nDay + "th ";
}

sDisplay += nYear;
cout << sDisplay;
 return true;
}

 

Endret 30. april 2008 av jj_

[jj_]

Tja, ser ut som jeg måtte ha med #include <sstream> , nå virker det i allefall:

 

 

// DateIO.cpp
//
// Program to recieve, validate and display a date.
//
// Original Code: M.Mason
// Modified by: <<insert your name here >>
//

#include <iostream>
#include <iomanip>
#include <sstream>

using namespace std;

// Function Prototypes
bool GetDate(int &nDay, int &nMonth, int &nYear);
bool ValidDate(int nDay, int nMonth, int nYear);
bool DisplayDate(int nDay, int nMonth, int nYear);

// Main
int main(int argc, char *argv[]){
 int nFirstDay;
 int nFirstMonth;
 int nFirstYear;

 do {
  GetDate(nFirstDay, nFirstMonth, nFirstYear);
 } while ( !ValidDate(nFirstDay, nFirstMonth, nFirstYear) );

 DisplayDate(nFirstDay, nFirstMonth, nFirstYear);

 return 0;
}

// Function implementations ...

// bool GetDate(int &nDay, int &nMonth, int &nYear)
// prompts user for the day, the month and the year (seperately)
// checks to see that it got numbers.  
bool GetDate(int &nDay, int &nMonth, int &nYear){
do{	
	if (cin.fail()){
		cin.clear();
		while (cin.get() != '\n');
		cout << "\nAn error occured: Expected integers\n";
	}

	cout << "Enter date (dd mm yyyy): ";
	cin >> nDay >> nMonth >> nYear;
} while (!cin.good());

 return true;
}


// bool ValidDate(int nDay, int nMonth, int nYear)
// Checks the values of nDay, nMonth and nYear to see if they form a valid date.
// returns false if the year is invalid.
bool ValidDate(int nDay, int nMonth, int nYear){
string sDay = "" + nDay;
string sMonth = "" + nMonth;
string sYear = "" + nYear;
bool bErr = false;

if (nDay < 1 || nDay > 31) bErr = true;
if (nMonth < 1 || nMonth > 12) bErr = true;
if (nYear < 1900 || nYear > 2008) bErr = true;

if (bErr){
	cout << "\nError in date format, please try again\n";
	return false;
} else {
	return true;
}
}

// bool DisplayDate(int nDay, int nMonth, int nYear)
// Writes the date out to the cout stream in MM DD YYYY format
bool DisplayDate(int nDay, int nMonth, int nYear){
string sMonth;
string sDay;
string temp;
stringstream convert;

enum months{
	jan = 1,
	feb, mar, apr, may, jun, jul,
	aug, sep, oct, nov, dec};

switch (nMonth){
	case jan:
		sMonth = "January ";
		break;
	case feb:
		sMonth = "February ";
		break;
	case mar:
		sMonth = "March ";
		break;
	case apr:
		sMonth = "April ";
		break;
	case may:
		sMonth = "May ";
		break;
	case jun:
		sMonth = "June ";
		break;
	case jul:
		sMonth = "July ";
		break;
	case aug:
		sMonth = "August ";
		break;
	case sep:
		sMonth = "September ";
		break;
	case oct:
		sMonth = "October ";
		break;
	case nov:
		sMonth = "November ";
		break;
	case dec:
		sMonth = "December ";
		break;
}

//set temp = nDay
convert << nDay;
temp = convert.str();

if(nDay > 20){
	temp = temp.substr(1,1);
}

if (temp == "1"){
	sDay = "st ";
} else if (temp == "2"){
	sDay = "nd ";
} else if (temp == "3"){
	sDay = "rd ";
} else {
	sDay = "th ";
}

cout << sMonth << nDay << sDay << nYear << endl;

 return true;
}