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problem with classes in C++

mihafan (3)
created class of 'natural numbers' for arithmetic operations I started writing code
I started to solve correctly???
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#include<iostream.h>
#include<conio.h>
#include<fstream.h>
#include<math.h>
#include<string.h>
class natural{
public :
char x[10000];

friend natural operator+(natural,natural);
friend natural operator+(natural,unsigned int);
friend natural operator-(natural,natural);
friend natural operator-(natural,unsigned int);
friend natural operator*(natural,natural);
friend natural operator/(natural,natural);
friend int operator==(natural,natural);
natural operator=(natural);
friend ostream& operator << (ostream& os,natural z);
friend istream& operator >> (istream& is,natural z);    };

natural operator+(natural a,natural b){
natural c;
int o[1000],m[1000],n[1000],l,l1,lt,d,r,i;
for(i=0;i<strlen(a.x);i++)
m[i]=a.x[i]-48;
for(i=0;i<strlen(b.x);i++)
n[i]=b.x[i]-48;  l=strlen(a.x); l1=strlen(b.x);
if(l>l1) {lt=l; d=l-l1;
for(i=l1-1;i>=0;i--)
n[i+d]=n[i];
for(i=0;i<d;i++)
n[i]=0; }
else  {lt=l1; d=l1-l;
for(i=l-1;i>=0;i--)
m[i+d]=m[i];
for(i=0;i<d;i++)
m[i]=0; }
r=0;
for(i=lt-1;i>-1;i--)
{o[i]=(m[i]+n[i]+r)%10; r=(m[i]+n[i])/10;
}
for(i=0;i<lt;i++)
c.x[i]=o[i]+48;
return c;}

natural operator+(natural a,unsigned int b){
natural c;
int o[1000],m[1000],n[1000],l1,l2,lt,d,r,i;
for(i=0;i<strlen(a.x);i++)
m[i]=a.x[i]-48;
lt=l2=strlen(a.x);
l2--;
while(b!=0)
{n[l2]=b%10;
b=b/10;l2--; }
for(i=0;i<=l2;i++)
n[i]=0;
for(i=0;i<lt;i++)
 cout<<n[i];
   cout<<endl;
r=0;
for(i=lt-1;i>-1;i--)
{o[i]=(m[i]+n[i]+r)%10; r=(m[i]+n[i])/10;
}
for(i=0;i<lt;i++)
c.x[i]=o[i]+48;
return c;}

natural operator-(natural a,natural b){
natural c;
int o[1000],m[1000],n[1000],l,l1,lt,d,r,i;
for(i=0;i<strlen(a.x);i++)
m[i]=a.x[i]-48;
for(i=0;i<strlen(b.x);i++)
n[i]=b.x[i]-48;  l=strlen(a.x); l1=strlen(b.x);
if(l>l1) {lt=l; d=l-l1;
for(i=l1-1;i>=0;i--)
n[i+d]=n[i];
for(i=0;i<d;i++)
n[i]=0; }
else  {lt=l1; d=l1-l;
for(i=l-1;i>=0;i--)
m[i+d]=m[i];
for(i=0;i<d;i++)
m[i]=0; }
r=0;
for(i=lt-1;i>-1;i--)
{if((m[i]>n[i]) ||(m[i]==n[i])) o[i]=m[i]-n[i];
 else {o[i]=m[i]+10-n[i]; r=i; m[r-1]--; }
 }
for(i=0;i<lt;i++)
c.x[i]=o[i]+48;
return c;}

natural operator-(natural a,int b){
natural c;
int o[1000],m[1000],n[1000],l,l1,lt,d,r,i;
for(i=0;i<strlen(a.x);i++)
m[i]=a.x[i]-48;
lt=l1=strlen(a.x);
l1--;
while(b!=0)
{n[l1]=b%10;
b=b/10;l1--; }
for(i=0;i<=l1;i++)
n[i]=0;
for(i=0;i<lt;i++)
cout<<n[i];cout<<endl;

r=0;
for(i=lt-1;i>-1;i--)
{if((m[i]>n[i]) ||(m[i]==n[i])) o[i]=m[i]-n[i];
 else {o[i]=m[i]+10-n[i]; r=i; m[r-1]--; }
 }
for(i=0;i<lt;i++)
c.x[i]=o[i]+48;
return c;}


int operator==(natural a,natural b)  { int ok;ok=1;
if(strlen(a.x)!=strlen(b.x)) ok=0;
else {for(int i=0;i<strlen(a.x);i++)
     if(a.x[i]!=b.x[i])
	   ok=0;  }
if (ok!=1) return 0;
else return 1;
}

ostream& operator << (ostream& os,natural z){
for(int i=0;i<strlen(z.x);i++)
os<<z.x[i];
return os;}

istream& operator >> (istream& is,natural& z){
is>>z.x;
return is;}

main ()
{clrscr();
natural w,y;
unsigned int t;
 char f;

do{
 cout<<"1-natural+natural"<<endl;
 cout<<"2-natural+int"<<endl;
 cout<<"3-natural-natural"<<endl;
 cout<<"4-natural-int"<<endl;
 cout<<"5-natural*natural"<<endl;
 cout<<"6-natural/natural"<<endl;
 cout<<"0-exit"<<endl;
 cin>>f;
  switch(f)
  {
   case '1': cout<<"---------natural+natural--------"<<endl;
 cout<<"introdu valoarea numarului natural"<<"\n";
 cin>>w.x;
  cin>>y.x;
   cout<<"valorile introduse:"<<"\n";
cout<<"w="<<w<<"\n";
cout<<"y="<<y<<"\n";
 cout<<w+y<<endl;
 if(w==y)
cout<<"numerele sint egale";
else cout<<"numerele sint diferite"; cout<<endl;
break;
case '2': cout<<"--------natural + int------"<<endl;
 cout<<"dati un nr natural:";
 cin>>w.x;
  cout<<"dati un nr int:";
 cin>>t;
 cout<<w+t<<endl;  break;
 case '3':cout<<"-----------natural-natural------------"<<endl;
 cout<<w-y<<endl; break;
  default : cout<<"operatie necunoscuta:";cout<<endl;}}
   while(f!='0');

}
jsmith (5804)
Well, your coding technique is unreadable. The space bar and the ENTER keys are your friends...

Also, somehow, without even trying to understand what you are doing, I think that the operators can be implemented in less than 9 local variables. Consider simplifying the code.

Having said that, operator== should return bool, not int;
operator= should return natural& (ie, *this);

Consider using boost::operators for a lot of this; you'll get a bunch of the functions for free.

and - 48 would be better written as - '0'
Last edited on
jloundy (172)
holy santa clause shit, Im lost
mihafan (3)

how to write constructor and destructor for this class??????????????
Bazzy (6281)
Just one question mark is enough

to write a constructor you need to put in the class a function with no return type specified and the same name of the class,
for the destructor the same thing but adding a ~ before the class name:
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class C
{
    public:
        C(/*parameters*/) : initializer(list) { /*constructor body*/ }
        ~C() { /*destructor body*/  }
}

http://www.cplusplus.com/doc/tutorial/classes/
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