Why does it not work? | Together C & C++ | Page 1

atomic parrot Jan 17, 2023, 1:42 AM

#

#include<iostream>
#include<cmath>
#include<iomanip>
#include<algorithm>
#include <string>
#include <typeinfo>
#include <functional>
#include <concepts>
#include <cmath>
#include<ostream>
using namespace std;
template<typename T>
concept Number = integral<T> || floating_point<T>;

int constexpr inline countDigit(long long n)
{
    if (n/10 == 0)
        return 1;
    return 1 + countDigit(n / 10);
}
int constexpr inline sign(int y){
    return clamp(y,-1,1);
}
//#define sign(n) clamp(n,-1,1);
template<typename T,typename E,typename K>
requires Number<T> && Number<E> && Number<K>
class graph{
    private:
    T(*GraphFunc)(E,K);
    public: 
    void plot();

};
template<typename T,typename E,typename K>
void graph::plot(){
    int z;
    for(int y=-15;y<=15;y++){
        if (y%5==0){cout<<setw(countDigit(15)+2)<<-y;}else{cout<<setw(countDigit(15)+4);}
        cout<< (y%5==0?"-|":"|");
        for(int x=-15;x<=15;x++){
            z = sign(GraphFunc(x,y))+sign(GraphFunc(x-1,y))+sign(GraphFunc(x,y-1))+sign(GraphFunc(x-1,y-1)); 
            if ((z<4) && (z>-4)){
                cout<<"--";
            } else if(y==0) {
                cout<<"- ";
            } else{
                cout<<"  ";
            }
        }   
}
int main(){}

foggy sphinxBOT Jan 17, 2023, 1:42 AM

#

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potent path Jan 17, 2023, 1:48 AM

#

atomic parrot ```cpp #include<iostream> #include<cmath> #include<iomanip> #include<algorithm> ...

;compile -std=c++20

errant pawnBOT Jan 17, 2023, 1:48 AM

#

Compiler Output

<source>:35:6: error: 'template<class T, class E, class K>  requires (Number<T>) && (Number<E>) && (Number<K>) class graph' used without template arguments
   35 | void graph::plot(){
      |      ^~~~~
<source>: In function 'void plot()':
<source>:41:22: error: there are no arguments to 'GraphFunc' that depend on a template parameter, so a declaration of 'GraphFunc' must be available [-fpermissive]
   41 |             z = sign(GraphFunc(x,y))+sign(GraphFunc(x-1,y))+sign(GraphFunc(x,y-1))+sign(GraphFunc(x-1,y-1));
      |                      ^~~~~~~~~
<source>:41:22: note: (if you use '-fpermissive', G++ will accept your code, but allowing the use of an undeclared name is deprecated)
<source>:41:43: error: there are no arguments to 'GraphFunc' that depend on a template parameter, so a declaration of 'GraphFunc' must be available [-fpermissive]
   41 |             z = sign(GraphFunc(x,y))+sign(GraphFunc(x-1,y))+sign(GraphFunc(x,y-1))+sign(GraphFunc(x-1,y-1));
      |

atomic parrot Jan 17, 2023, 2:14 AM

#

potent path ;compile -std=c++20

yah and what does it mean

cold plover Jan 17, 2023, 2:16 AM

#

Check the compilation output to find out your mistakes

atomic parrot Jan 17, 2023, 2:21 AM

#

cold plover Check the compilation output to find out your mistakes

no idea what it means

graceful vapor Jan 17, 2023, 2:22 AM

#

without template arguments
35 | void graph::plot()

atomic parrot Jan 17, 2023, 2:30 AM

#

;compile cpp -std=c++20```cpp
#include<iostream>
#include<cmath>
#include<iomanip>
#include<algorithm>
#include <string>
#include <typeinfo>
#include <functional>
#include <concepts>
#include <cmath>
#include<ostream>
using namespace std;
template<typename T>
concept Number = integral<T> || floating_point<T>;

int constexpr inline countDigit(long long n)
{
if (n/10 == 0)
return 1;
return 1 + countDigit(n / 10);
}
int constexpr inline sign(int y){
return clamp(y,-1,1);
}
//#define sign(n) clamp(n,-1,1);
template<typename T,typename E,typename K>
requires Number<T> && Number<E> && Number<K>
class graph{
private:
T(*GraphFunc)(E,K);
public:
void plot();

};

template<typename T,typename E,typename K>
void graph::plot(){
int z;
for(int y=-15;y<=15;y++){
if (y%5==0){cout<<setw(countDigit(15)+2)<<-y;}else{cout<<setw(countDigit(15)+4);}
cout<< (y%5==0?"-|":"|");
for(int x=-15;x<=15;x++){
z = sign(GraphFunc(x,y))+sign(GraphFunc(x-1,y))+sign(GraphFunc(x,y-1))+sign(GraphFunc(x-1,y-1));
if ((z<4) && (z>-4)){
cout<<"--";
} else if(y==0) {
cout<<"- ";
} else{
cout<<" ";
}
}
}
int main(){}

errant pawnBOT Jan 17, 2023, 2:31 AM

#

Compiler Output

<source>:36:6: error: 'template<class T, class E, class K>  requires (Number<T>) && (Number<E>) && (Number<K>) class graph' used without template arguments
   36 | void graph::plot(){
      |      ^~~~~
<source>: In function 'void plot()':
<source>:42:22: error: there are no arguments to 'GraphFunc' that depend on a template parameter, so a declaration of 'GraphFunc' must be available [-fpermissive]
   42 |             z = sign(GraphFunc(x,y))+sign(GraphFunc(x-1,y))+sign(GraphFunc(x,y-1))+sign(GraphFunc(x-1,y-1));
      |                      ^~~~~~~~~
<source>:42:22: note: (if you use '-fpermissive', G++ will accept your code, but allowing the use of an undeclared name is deprecated)
<source>:42:43: error: there are no arguments to 'GraphFunc' that depend on a template parameter, so a declaration of 'GraphFunc' must be available [-fpermissive]
   42 |             z = sign(GraphFunc(x,y))+sign(GraphFunc(x-1,y))+sign(GraphFunc(x,y-1))+sign(GraphFunc(x-1,y-1));
      |

atomic parrot Jan 17, 2023, 2:31 AM

#

graceful vapor without template arguments 35 | void graph::plot()

stil mo

silver arch Jan 17, 2023, 8:13 AM

#

I mean the first error is pretty clear

hollow spoke Jan 17, 2023, 9:40 AM

#

atomic parrot ;compile cpp -std=c++20```cpp #include<iostream> #include<cmath> #include<iomani...

member function declarations need to know the templates used

template<typename T,typename E,typename K>
void graph<T,E,K>::plot(){

#

how do you not know the basics...

#

and yet know how to use C++20 concepts

foggy sphinxBOT Jan 17, 2023, 9:46 PM

#

This question thread is being automatically closed. If your question is not answered feel free to bump the post or re-ask. Take a look at !howto ask for tips on improving your question.

foggy sphinxBOT Jan 18, 2023, 10:46 AM

#

This question thread is being automatically marked as solved.

atomic parrot Jan 18, 2023, 10:08 PM

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hollow spoke member function declarations need to know the templates used ``` template<typena...

bozo me

hollow spoke Jan 19, 2023, 10:23 AM

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silver arch I mean the first error is pretty clear

I expected you to see and explain this, but you did not, how?

#Why does it not work?