Why does my code not display updated dates? [closed] - c++

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Okay so what this program is supposed to do is display the date in M/D/Y format and for some unknown reason it always displays 1/1/1. I have been skimming through this the past 40 mins and still can't understand where I went wrong. Please help me out. Needmorewordstopostthissssssssssssssssssssssssssssssssssssssssssssssss
#include <iostream>
using namespace std;
void displayDate();
class Date{
public:
int month;
int day;
int year;
int mmax;
//functions
int getMonth();
int getDay();
int getYear();
int setMonth();
int setDay();
int setYear();
};
int Date::setMonth(){
int i;
for (i=1; i!=0; i=1)
{
cout << "\n Input the month: ";
cin >> month;
if (month < 1) {
cout << "Please input a valid month";
}
else if (month > 12){
cout << "Please input a valid month";
}
else{
break;
}
}
return month;
}
int Date::setDay(){
int i;
for (i=1; i!=0; i=1)
{
cout << "\n Input the day: ";
cin >> day;
if (day < 1) {
cout << "Please input a valid day";
}
else if ((month == 1 || 3 || 5 || 7 || 8 || 10 || 12) && (day > 31)){
cout << "Please input a valid day";
}
else if ((month == 4 || 6 || 9 || 11) && (day > 30)){
cout << "Please input a valid day";
}
else if ((month == 2) && (day > 28)){
cout << "Please input a valid day";
}
else{
break;
}
}
return day;
}
int Date::setYear(){
int i;
for (i=1; i!=0; i=1)
{
cout << "\n Input the year: ";
cin >> year;
if (year < 1) {
cout << "Please input a valid year";
}
else if (year > 2021){
cout << "Please input a valid year";
}
else{
break;
}
}
return year;
}
int Date::getMonth(){
int month;
return month;
}
int Date::getDay(){
int day;
return day;
}
int Date::getYear(){
int year;
return year;
}
void displayDate(int d,int m, int y){
cout << "Date: " <<m;
cout << "/" <<d;
cout << "/" <<y;
}
main(){
Date x;
int m,d,y;
x.setMonth();
x.setDay();
x.setYear();
m = x.getMonth();
d = x.getDay();
y = x.getYear();
displayDate(d, m ,y);
}

Answer 1

In your code, the getter is not returning the class member variables rather the local variables delared.
int Date::getMonth(){
return month;
}
int Date::getDay(){
return day;
}
int Date::getYear(){
return year;
}
Make the getters like this to return the actual member value.

Answer 2

int Date::getYear(){
int year;
return year;
}
In here, you declare a new int year; variable, that is not initialized, then you return that variable instead of the member variable of your class.
Change it to
int Date::getYear(){
return year;
}
Similar for your other get() functions.
Your conditions are also not working as you want it to:
(month == 1 || 3 || 5 || 7 || 8 || 10 || 12)
doesn't compare month to all those numbers, the numbers just all evaluate to true. The condtion should be:
(month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12)

Answer 3

I have tried to fix a number of problems in your code. And I have added comments explaining why:
#include <iostream>
// using namespace std; // avoid it if you can. It brings too many symbol in main workspace
using std::cout;
using std::cin;
void displayDate();
class Date{
private: // attributes should be private, only accessors should be public (encapsulation)
int month;
int day;
int year;
//int mmax; // comment out member that the code does not (still) use
//functions
public:
int getMonth();
int getDay();
int getYear();
int readMonth(); // setMonth should be a setter: int setMonth(int month) { this->month = month;}
int readDay();
int readYear();
};
int Date::readMonth(){
for (;;) // idiomatic form for an endless loop
{
cout << "\n Input the month: ";
cin >> month;
if (month < 1) {
cout << "Please input a valid month";
}
else if (month > 12){
cout << "Please input a valid month";
}
else{
break;
}
}
return month;
}
int Date::readDay(){
for (;;)
{
cout << "\n Input the day: ";
cin >> day;
if (day < 1) {
cout << "Please input a valid day";
}
else if (day > 31){ // other conditions were useless
cout << "Please input a valid day";
}
else if ((month == 4 || month == 6 || month == 9 || month == 11) && (day > 30)){ // fix
cout << "Please input a valid day";
}
else if ((month == 2) && (day > 28)){
cout << "Please input a valid day";
}
else{
break;
}
}
return day;
}
int Date::readYear(){
for (;;)
{
cout << "\n Input the year: ";
cin >> year;
if (year < 1) {
cout << "Please input a valid year";
}
else if (year > 2021){
cout << "Please input a valid year";
}
else{
break;
}
}
return year;
}
int Date::getMonth(){
//int month; // the local variable would hide the member
return month;
}
int Date::getDay(){
//int day;
return day;
}
int Date::getYear(){
//int year;
return year;
}
void displayDate(int d,int m, int y){
cout << "Date: " <<m;
cout << "/" <<d;
cout << "/" <<y;
cout << '\n'; // do not forget end of lines
}
int main(){ // main shall be declared to return int
Date x;
int m,d,y;
x.readMonth();
x.readDay();
x.readYear();
m = x.getMonth();
d = x.getDay();
y = x.getYear();
displayDate(d, m ,y);
return 0; // better to be explicit
}
Other things could be improved, because re-usability is important in OOP. But I am too lazy to go further today ;-)