Help me

#include<iostream> using namespace std; int main(){     int num,i;     cout<<"Enter a number:";     cin>>num;     for(i=2;i<num;i++){         if(num%i==0){             cout<<num<<" is not a prime number";             break;         }         else{             cout<<num<<" is a prime number";             break;         }     }     return 0; }

#include<iostream> using namespace std; int main(){     int num,i;     cout<<"Enter a number:";     cin>>num;     for(i=2;i<num;i++){         if(num%i==0){             cout<<num<<" is not a prime number";             break;         }         else{             cout<<num<<" is a prime number";             break;         }     }     return 0; }

It is not valid in UTF-16...neither in UTF-8 which is why I asked if you are using the right encoding. Here I am not talking about the Unicode standard. I am talking about the C++ standard. The problem is that the C++ standard specifies that \u accepts only code points and not code units. You are specifying a surrogate pair using \u specification which is specifically forbidden by the C++ standard. Unless you show me how you are encoding the string (meaning you show me the code), there is not much I can tell you. By default the values in a string are printed out assuming the local machine's encoding. Unless you specify the encoding correctly, the values printed out will not be meaningful. And also your terminal should be able to support the encoding used. Unless all of this happens, you will not be able to see the correct output that you expect.

Well, C++ also says that any utf codepoint above 127 is undefined behaviour for that matter

#include<iostream> Using namespace std; Int main (){ Int num ,I; Cout<<"enter the num"<<endl; Cin>>num; For(I=2;I<num;I++){ If (num%i==0){ Cout<<"it is not prime"<<endl; break; } } If (I==num){ Cout<<"it is prime num"<<endl; } }

Where does it say that?

God helps if i remember the exact page but that was in a footnote about utf8 support

"A universal-character-name designates the character in ISO/IEC 10646 (if any) whose code point is the hexadecimal number represented by the sequence of hexadecimal-digits in the universal-character-name.   The program is ill-formed if that number is not a code point or if it is a surrogate code point.   Noncharacter code points and reserved code points are considered to designate separate characters distinct from any ISO/IEC 10646 character." [Note 1:  ISO/IEC 10646 code points are integers in the range [0,10FFFF] (hexadecimal).   A surrogate code point is a value in the range [D800,DFFF] (hexadecimal).   A control character is a character whose code point is in either of the ranges [0,1F] or [7F,9F] (hexadecimal).  — end note] This is what I was referring to in my message that you replied to.

You can't represent UTF-8, if you restrict a char8_t byte to the range 0-127. I think you misunderstood the standard.

Oh no i didn't, if i was then my team was also misunderstanding it. But these types of shortcuts in standardisation are common tbf, it is what allows smaller c++ compiler to slowly evolve by giving leeway to the implementation

Oh no i didn't, if i was then my team was also misunderstanding it. But these types of shortcuts in standardisation are common tbf, it is what allows smaller c++ compiler to slowly evolve by giving leeway to the implementation

can any one tell me what's the error in this code?

It's fine

void ftoc(int a, int b, int j) { while (a <= b) { int c = (5.0 / 9) * (a - 32); cout << a << "\t" << c; cout << endl; a += j; } }

This function tries to modify parameter received as value, not as pointer (a+=j). It's not possible.

What???

I mean modification of 'a' will not be visible to caller (in case if that was expected).

What makes you think he wants the modification to be visible? All that he is doing is printing out Fahrenheit to Celsius table.

Is this a good way to store string in char array using vectors Or there is any better approach ? int main(){ string name="Honey Bansal"; vector <char> name_arr(name.begin(),name.end()); for(int i=0;i<name_arr.size();++i){ cout<<name_arr[i]; } return 0; }

Yes this is a good way to achieve this. However it would be even better to just keep the string instead.

You mean working with string is much better than using char ?

What are you trying to do with the string?

working with databases, so I want as many functions I can use on string or char_array.

In this case I would argue it makes more sense to keep the string (which is basically a char array)

okay..

otherwise you end up allocating more memory, end up performing unnecessary copies and so on.

Is is it a good way of printing string using pointers ? void printString(string *s){ cout<<*s; } int main(){ string name="Honey Bansal"; printString(&name); return 0; }

Then why are you asking us to identify the error in the code?

yes, that's fine. However it might be even better to use a const reference instead of a pointer (e.g. because the reference can't be null).

#include<iostream> using namespace std; int main(){ int cp >= 0; int spp >= 0; cout<<"enter the cost prise "<<endl; cin>>cp; cout<<"enter the selling prise "<<endl; cin>>spp; if (cp>spp) { cout<<"you made a proffit of "; else { cout<<"you enter a odd number"; } return 0;

#include<iostream> using namespace std; int main(){ int cp >= 0; int spp >= 0; cout<<"enter the cost prise "<<endl; cin>>cp; cout<<"enter the selling prise "<<endl; cin>>spp; if (cp>spp) { cout<<"you made a proffit of "; else { cout<<"you enter a odd number"; } return 0;

Weird

Please help

#include<iostream> using namespace std; int main(){ int cp >= 0; int spp >= 0; cout<<"enter the cost prise "<<endl; cin>>cp; cout<<"enter the selling prise "<<endl; cin>>spp; if (cp>spp) { cout<<"you made a proffit of "; else { cout<<"you enter a odd number"; } return 0;

Is is it a good way of printing string using pointers ? void printString(string *s){ cout<<*s; } int main(){ string name="Honey Bansal"; printString(&name); return 0; }

How could I include my cpp files into other file just like we include iostream and conio.h and all

#include <iostream> int main() { int cp; std::cin >> cp; if (cp <= 0) { std::cout << "Cost price shouldn't be less than or 0" << std::endl; exit(1); } int profit; std::cin >> profit; if (profit <= 0) { std::cout << "Selling price shouldn't be less than or 0"; exit(1); } profit -= cp; if (profit > 0) std::cout << "Profit: " << profit; else std::cout <<" In loss of: " << profit; return 0; }

Why did you used std everywhere?

No it is not a good idea to use raw pointers in Modern C++. Raw pointer parameters place an additional burden on the caller to determine if the pointer needs to be allocated on the heap or it can be a pointer to data allocated on the stack. This could depend on what is being done inside the code of the called function. Smart pointers help alleviate this problem to an extent but you don't want to use them unless absolutely necessary. Use references to avoid this problem. If the called function doesn't have to change the reference (the name of the function should give you an idea) then it should be a const reference. Otherwise it can be a plain reference. If you want a function to accept only prvalues, then it should be a rvalue reference.

Is this what you are saying ? void printString(const string &s){ cout<<s<<endl; } int main() { string s="hello world"; printString(s); return 0; }

Because didn't declare it in global namespace

Is this what you are saying ? void printString(const string &s){ cout<<s<<endl; } int main() { string s="hello world"; printString(s); return 0; }

I actually don't understand the use of printString() func tbh