Input check problem with numbers
Which is the most suitable source code? I need a programmer with a large experience on C++ to answer this question.
Code:
#include <string>
#include <iostream>
#include <limits>
int main() {
using namespace std;
const int THISYEAR = 2007;
string yourName;
int birthYear,bad_input;
cout << "What's your name ? " << flush;
getline(cin, yourName);
do {
bad_input=0;
cout <<"\nWhat year were you born :" << flush ;
cin >> birthYear;
if(!cin.good())
{
bad_input=1;
cin.clear();
cin.ignore(numeric_limits<streamsize>::max(),'\n');
cout << "This is not valid value" << endl;
}
}while(bad_input);
cout << "Your name is " << yourName
<< " and you are approximately "
<< (THISYEAR-birthYear)
<< " years old. " << endl;
return 0;
}
2nd:
Code:
#include <string>
#include <iostream>
#include <limits>
int main() {
using namespace std;
const int THISYEAR = 2007;
string yourName;
int birthYear;
cout << "What's your name ? " << flush;
getline(cin, yourName);
cout <<"What year were you born? " << flush;
while(!(cin>>birthYear))
{
cin.clear();
cin.ignore(numeric_limits<streamsize>::max(),'\n');
cout << "No valid value. ";
cout <<"What year were you born? " << flush;
}
cout << "Your name is " << yourName
<< " and you are approximately "
<< (THISYEAR-birthYear)
<< " years old. " << endl;
return 0;
}
3rd
Code:
#include <string>
#include <iostream>
#include <cstdlib>
int main() {
using namespace std;
const int THISYEAR = 2007;
string yourName;
int birthYear;
char temp[100];
cout << "What's your name ? " << flush;
getline(cin, yourName);
do {
cout <<"What year were you born? " << flush;
cin.getline(temp,100);
birthYear=atoi(temp);
if (birthYear==0) {
cout << "Invalid valude..." << flush;
}
} while(birthYear==0);
cout << "Your name is " << yourName
<< " and you are approximately "
<< (THISYEAR-birthYear)
<< " years old. " << endl;
return 0;
}
5th
Code:
#include <string>
#include <iostream>
#include <sstream> // for istringstream convert()
using namespace std;
int main()
{
const int THISYEAR = 2007;
string yourName;
int birthYear;
string birth; //για το έτος γέννησης
cout << "What's your name ? " << flush;
getline(cin,yourName);
for(;1;) {
cout << "What year were you born? ";
getline(cin,birth);
// μετατροπή string -----> int
istringstream convert(birth);
// τοποθέτηση στην int birthYear
convert >> birthYear;
// αν δεν πετύχει σημαίνει ότι δεν είναι αριθμός
if(!convert {
cout << " This is not valid.Try again...." << endl;
continue;
} else {
break;
}
}
cout << "Your name is " << yourName
<< " and you are approximately "
<< (THISYEAR-birthYear)
<< " years old. " << endl;
return 0;
}
6th
Code:
#include <string>
#include <iostream>
#include <cstdlib> //Για να κάνεις calls σε commands από το prompt π.χ. την PAUSE, επίσης έχει την atoi
#pragma argsused
//Ελέγχει εαν το string περιέχει αριθμό
// εαν ναι επιστρέφει true
// αλλιώς επιστρέφει false
bool CheckStr(const std::string& s)
{
for (int i = 0; i < s.length(); i++) {
if (!std::isdigit(s[i]))
return false;
}
return true;
}
//Παίρνει το όνομα
void GetName(std::string& yourName)
{
using namespace std;
cout << "What's your name ? " << flush;
getline(cin, yourName);
}
//Παίρνει την ημ. γέννησης
void GetBirthdate(std::string& birthYear)
{
using namespace std;
cout << "What year were you born? ";
getline(cin, birthYear);
}
int main(int argc, char* argv[])
{
using namespace std;
const int THISYEAR = 2007;
string yourName;
string birthYear;
int intYear;
bool exit = false;
//Μέχρι να δώσει σωστή ημ. ο χρήστης το πρόγραμμα κάνει loop
while (!exit)
{
GetName(yourName); //Παίρνει το όνομα
GetBirthdate(birthYear); //Παίρνει την ημ. γέννησης
if ( CheckStr(birthYear) ) { //Εάν η ημερομηνία είναι σωστή
intYear = atoi(birthYear.c_str() ); //Μετατρέπει το string σε integer
cout << "Your name is " << yourName
<< " and you are approximately "
<< (THISYEAR-intYear)
<< " years old. " << endl;
exit = true;
}
else {
cerr << "This is not valid."
<< " Try again..." << endl;
}
}
system("PAUSE");
return 0;
}
Thanx for your time
