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Help Guys!!!

pavlkons (2)
Hello I'm Pavlos from Greece I'm new in C++ i have an asignment for my exams and i have a problem in this programm(look down). most of the variables are named in greeklish so you might not understand the use. My problem is with the extern variables I have in line 10 (min and max). i have this error "106 C:\Users\pavlos\Desktop\lab_3_2.cpp.cpp `max' undeclared (first use this function)", BUT the funny think is that I'm using the variables p and f in the same way and I don't get an error about them. What's the problem with min and max?????????????? (It will help you if you copy it in Dev-C++ and you run it)
Thank you!!!







# include <iostream>
# include <stdlib.h>
# include <cstring>
using namespace std;


float mesos; //dhlwsh genikwn metavlhtwn
int p;
int f;
float min;
float max;

class student

{
private:
int am ;
char *onoma ;
int mathimata ;
float *vathmologia ;
float mo ;
int perase ;
int kopike ;
float minvathm ;
float maxvathm ;
public:
student ( int arithmos , char *name , int mathm , float *vathm ) {setstudent(arithmos,name,mathm,vathm);} //constructor
student () {mo=0, perase=0, kopike=0, minvathm=0, maxvathm=0;}
void setstudent(int arithmos , char *name , int mathm , float *vathm );
void calc(); //synarthshsh ypologismou
void emfanish(); //synarthsh ektypwshs
};


void student::setstudent(int arithmos , char *name , int mathm , float *vathm) //arxikopoihsh dedomenwn
{
am=0; onoma="NO NAME"; mathimata=0; vathmologia=0;

if (arithmos >=1 && arithmos <=9999 )
{
am = arithmos;
}

if (mathm >= 1 && mathm <=8)
{
mathimata = mathm;
}

onoma = new char [strlen(name)];

if (strlen(name)>=1 && strlen(name)<=40)
{
onoma = name ;
}

vathmologia = new float [mathm];

for (int i=0; i<=mathm ; i++)
{
if (vathm[i] >= 1 && vathm[i] <=10)
{
vathmologia[i] = vathm[i] ;
}
}
}

void student::calc()
{
float sum = 0 ; //ypologismos mesou orou
for (int i=0 ; i < mathimata ; i++ )
{
sum = sum + vathmologia[i];
}

mo = sum/mathimata;
mesos = mo ;

perase=0; kopike=0; //ypologismos mathimatwn pou perase kai kopike
for (int i=0 ; i < mathimata ; i++ )
{
if (vathmologia[i] < 5)
{
perase = perase +1;
}
else
{
kopike = kopike + 1;
}
}
p=perase;
f=kopike;

minvathm=10; maxvathm=0; //ypologismos min max
for (int i=0 ; i < mathimata ; i++ )
{
if (vathmologia[i] < minvathm)
{
minvathm = vathmologia[i];
}

if (vathmologia[i] > maxvathm )
{
maxvathm = vathmologia[i];
}
}
max=maxvathm;
min=minvathm;

}

void student::emfanish()
{
cout << "Name: " << onoma <<"\n" ;
cout << "id: " << am <<"\n" ;
cout << "Subjects Given: " << mathimata << "\n" ;
cout << "Grades Taken: " ;
for (int i=0 ; i < mathimata ; i++ )
{
cout << vathmologia[i] << " " ;
}
cout<<"\n";
}

int main()
{
student ant;
float vathm[] = {7.0, 3.0, 6.0, 10.0, 4.0};
ant.setstudent(1510, "James Stathatos", 5, vathm);
ant.emfanish();
//float min; float max;
ant.calc();
cout << "Passed in " << p << " Subjects, \n";
cout << "Failed in " << f << " Subjects \n";
cout << "Average Grade: " << mesos <<"\n";
cout << "Minimum Grade: " << min <<"\n";
cout << "Maximum Grade: " << max <<"\n";
system ("pause");
return 0 ;
}
Stewbond (2827)
posting with code tags so I can find line 106:
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# include <iostream>
# include <stdlib.h>
# include <cstring>
using namespace std;


float mesos; //dhlwsh genikwn metavlhtwn
int p; 
int f; 
float min; 
float max; 

class student

{
private:
int am ;
char *onoma ;
int mathimata ;
float *vathmologia ;
float mo ;
int perase ;
int kopike ;
float minvathm ;
float maxvathm ;
public:
student ( int arithmos , char *name , int mathm , float *vathm ) {setstudent(arithmos,name,mathm,vathm);} //constructor
student () {mo=0, perase=0, kopike=0, minvathm=0, maxvathm=0;}
void setstudent(int arithmos , char *name , int mathm , float *vathm );
void calc(); //synarthshsh ypologismou
void emfanish(); //synarthsh ektypwshs 
};


void student::setstudent(int arithmos , char *name , int mathm , float *vathm) //arxikopoihsh dedomenwn
{ 
am=0; onoma="NO NAME"; mathimata=0; vathmologia=0;

if (arithmos >=1 && arithmos <=9999 )
{
am = arithmos;
}

if (mathm >= 1 && mathm <=8)
{
mathimata = mathm;
}

onoma = new char [strlen(name)];

if (strlen(name)>=1 && strlen(name)<=40)
{
onoma = name ; 
}

vathmologia = new float [mathm];

for (int i=0; i<=mathm ; i++)
{
if (vathm[i] >= 1 && vathm[i] <=10)
{
vathmologia[i] = vathm[i] ; 
}
}
}

void student::calc()
{
float sum = 0 ; //ypologismos mesou orou
for (int i=0 ; i < mathimata ; i++ )
{
sum = sum + vathmologia[i];
}

mo = sum/mathimata;
mesos = mo ; 

perase=0; kopike=0; //ypologismos mathimatwn pou perase kai kopike
for (int i=0 ; i < mathimata ; i++ )
{
if (vathmologia[i] < 5)
{
perase = perase +1;
}
else
{
kopike = kopike + 1;
}
}
p=perase;
f=kopike;

minvathm=10; maxvathm=0; //ypologismos min max
for (int i=0 ; i < mathimata ; i++ )
{
if (vathmologia[i] < minvathm)
{
minvathm = vathmologia[i];
}

if (vathmologia[i] > maxvathm )
{
maxvathm = vathmologia[i]; 
}
}
max=maxvathm;
min=minvathm;

}

void student::emfanish()
{
cout << "Name: " << onoma <<"\n" ;
cout << "id: " << am <<"\n" ;
cout << "Subjects Given: " << mathimata << "\n" ;
cout << "Grades Taken: " ;
for (int i=0 ; i < mathimata ; i++ )
{
cout << vathmologia[i] << " " ;
}
cout<<"\n";
}

int main()
{
student ant;
float vathm[] = {7.0, 3.0, 6.0, 10.0, 4.0};
ant.setstudent(1510, "James Stathatos", 5, vathm);
ant.emfanish();
//float min; float max;
ant.calc();
cout << "Passed in " << p << " Subjects, \n";
cout << "Failed in " << f << " Subjects \n";
cout << "Average Grade: " << mesos <<"\n";
cout << "Minimum Grade: " << min <<"\n";
cout << "Maximum Grade: " << max <<"\n";
system ("pause");
return 0 ;
}
Last edited on
Stewbond (2827)
Found it.

The words max and min are already defined as a macro in stdlib.h.

In my stdlib.h I have the following: 
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#ifndef __cplusplus
#define max(a,b)    (((a) > (b)) ? (a) : (b))
#define min(a,b)    (((a) < (b)) ? (a) : (b))
#endif


using #include <cstdlib> instead of #include <stdlib.h>

This resolves part of the issue but it also appears that it is also defined in <xutility> which is called by another include.

To fix this replace using namespace std; with:
using std::cout; using std::endl;.

This is the problem with using namespace std;. If you try and make a global variable that happens to have the same name as something in std, you get a conflict.

ANother option is to just rename min and max.
Last edited on
pavlkons (2)
Thank you very much guys!!! that's a think I could ever imagine!!! I'll just remane the variables. thank you!
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