int calculateSum(int step) { if (step <= 0) return 0; int val; scanf("%d", &val); return (val + calculateSum(--step)); } int main() { int T, N; int sum; scanf("%d", &T); int i, j; for (i=0; i<T; i++) { scanf("%d", &N); sum = calculateSum(N); printf("Case #%d: %d\n", i + 1, sum); } return 0; }

May i know, what "val" variable for?

I assume because of Base *a; So in which cases would function overloading work without using a virtual function ?

When you use an object reference as a reference to the base class, and not to the derived one Just like in your situation Base* ptr = new Derived();

May i know, what "val" variable for?

For reading input

#include<iostream> #include<string> using namespace std; void input(string a, string b){ cout<<"Enter your username "<<endl; cin>>a; cout<<"Enter your password "<<endl; cin>>b; } int main(){ string uname, pass; input(uname, pass); //int i=0; for(int i=0; i<=3; i++) { if (uname=="Yakushi" && pass=="ABCK") { cout<<"login successful "; break; } else cout<<"Wrong username or password. Try again."<<endl; input(uname,pass); } cout<<"Bye bye"; return 0; }

Can anyone see what's wrong here ?

Can anyone see what's wrong here ?

Have you learn reference ?

whatever I input it shows wrong username

whatever I input it shows wrong username

Because the input is go to local variable, not outside function

For reading input

Input of the total number that we need?

Because the input is go to local variable, not outside function

Umm sorry I didn't get it

Umm sorry I didn't get it

The input goes to a and b variable which is only exist in input() function

It doesn't refer to uname and pass variable outside the function

Ohh

So should I just remove function and take input manually?

Or there is another way to use function here

Or there is another way to use function here

Yes, you could try type reference

So should I just remove function and take input manually?

This can be applied too

void input(string& a, string& b);

void input(string& a, string& b);

what's the difference between void input(string& a, string& b); and void input(string *a, string *b); ?

what's the difference between void input(string& a, string& b); and void input(string *a, string *b); ?

With type reference, you don't need to explicity pass the reference

what's the difference between void input(string& a, string& b); and void input(string *a, string *b); ?

From one you passing address And one you storing shared addresses

Similar to what std::cin do, it use type-reference

Which is why std::cin does not require the reference of the input but scanf require it

Here you guys are talking about call be refrence or any other topic?

With pointers void func(int *a, int *b) func(&ref, &ano_ref) With reference void func(int &a, int &b) func(ref, ano_ref)

Afaik, it's only aliases

What is ref and ano_ref

Sorry , but i am beginner

What is ref and ano_ref

some variables outside func function

With pointers void func(int *a, int *b) func(&ref, &ano_ref) With reference void func(int &a, int &b) func(ref, ano_ref)

is there any difference between those two in this case ?

some variables outside func function

Got it

I use the pass by pointers all the time.

With pointers void func(int *a, int *b) func(&ref, &ano_ref) With reference void func(int &a, int &b) func(ref, ano_ref)

It works noww. Thankuuu❤️

is there any difference between those two in this case ?

Nope Edit: reference can't be nullptr

but reference is commonly used with object

but reference is commonly used with object

why are they used with objects commonly ?

https://isocpp.org/wiki/faq/references

https://isocpp.org/wiki/faq/references#refs-vs-ptrs

any good resources on how to code C style C++? Also like to know what are the costs of doing so in a real-life production work

Hi guys! I have a program in C which checks number for repeated digits. It's done by using boolean array and the reason why I'm asking is that I can't completely understand it. To be exact, I'm not sure how does the if statement work on the line 16. I have my code on Hastebin as it's said in the rules. Here's the link https://hastebin.com/tojayeyaca.cpp Thank you in advance!

Hi everyone I am begginer Please help me for finding problem there #include<iostream> #include<cmath> using namespace std; int main(){ int n; cin>>n; if (10<=n<=99) cout<<pow((n/10+(n-n/10*10),2)); }

Hi everyone I am begginer Please help me for finding problem there #include<iostream> #include<cmath> using namespace std; int main(){ int n; cin>>n; if (10<=n<=99) cout<<pow((n/10+(n-n/10*10),2)); }

Not used curly bracket after if

Thanks

Not used curly bracket after if

but that doesn't fix anything, does it

the problem is the pow call which doesn't take int as first argument

ah nah, you just messed up the )

but that doesn't fix anything, does it

C++ solve sequentially that's why it not consider the condition

pow takes 2 parameters, you have only 1

the problem is the pow call which doesn't take int as first argument

I think it's correct we can check it too

pow takes 2 parameters, you have only 1

He has taken 2 parameters

I think it's correct we can check it too

yep, it will automatically convert it

He has taken 2 parameters

where

he has first (n/10+(n-n/10*10),2) and there is no second

,2 is the second one

no

that would have to be cout<<pow((n/10+(n-n/10*10),2),2);

What's the syntax for pow

alright, i'll look into the specification

nope... it seems it takes only float/double as first argument and int/float/double as the second

that would have to be cout<<pow((n/10+(n-n/10*10),2),2);

I think it's wrong may be I miss something becoz i have never seen two commas in pow

I think it's wrong may be I miss something becoz i have never seen two commas in pow

there is just one... the first argument doesn't make sense (because of the sequence operator) but there is no second argument

Hi everyone I am begginer Please help me for finding problem there #include<iostream> #include<cmath> using namespace std; int main(){ int n; cin>>n; if (10<=n<=99) cout<<pow((n/10+(n-n/10*10),2)); }

Is their any specific error

Is their any specific error

it doesn't compile due to test.cpp: In function ‘int main()’: test.cpp:9:10: error: no matching function for call to ‘pow(double)’ 9 | cout<<pow(static_cast<double>(n/10+(n-n/10*10),2)); because it has only one parameter

Thanks

there is just one... the first argument doesn't make sense (because of the sequence operator) but there is no second argument

Yup I got it my mistake 👍👍

Thanks dude

the problem is the pow call which doesn't take int as first argument

Ok understood

Is their any specific error

No thanks program is working now

Hi guys! I have a program in C which checks number for repeated digits. It's done by using boolean array and the reason why I'm asking is that I can't completely understand it. To be exact, I'm not sure how does the if statement work on the line 16. I have my code on Hastebin as it's said in the rules. Here's the link https://hastebin.com/tojayeyaca.cpp Thank you in advance!

The while loop before the if condition would end only if n becomes 0 or if it breaks out early. It will break out early only if a repeated digit is present and in that case n will still be greater than 0 when the code breaks out of the while loop. If there is no repeated digit then the while loop will exit normally when n becomes 0 due to repeated division by 10. The if condition just checks whether the loop ended normally or prematurely.

#include<iostream> #include<vector> using namespace std; int main(){ vector<int> v1; for(int i=1; i<5; i++) v1.push_back(i); cout<<v1.size()<<endl; cout<<v1.capacity()<<endl; v1.resize(7); cout<<v1.size(); v1.shrink_to_fit(); for(auto it=v1.begin(); it!=v1.end(); i++) cout<<*it; return 0; }

Why it shows error in data type

Hi everyone I am begginer Please help me for finding problem there #include<iostream> #include<cmath> using namespace std; int main(){ int n; cin>>n; if (10<=n<=99) cout<<pow((n/10+(n-n/10*10),2)); }

if n is int your math wil be truncted. For exmple, 99/10 returns 9. To return 9.9 use 99/10.0

if n is int your math wil be truncted. For exmple, 99/10 returns 9. To return 9.9 use 99/10.0

Can u help mine problem

Can u help mine problem

#include <vector> mb?

#include <vector> mb?

??

Sorry but i cant understand

#include <iostream> #include <vector> using namespace std; int main(){ vector<int> v1; for(int i=1; i<5; i++) v1.push_back(i); cout<<v1.size()<<endl; cout<<v1.capacity()<<endl; v1.resize(7); cout<<v1.size(); v1.shrink_to_fit(); for(auto it=v1.begin(); it!=v1.end(); it++) cout<<*it; return 0; }

#include <iostream> #include <vector> using namespace std; int main(){ vector<int> v1; for(int i=1; i<5; i++) v1.push_back(i); cout<<v1.size()<<endl; cout<<v1.capacity()<<endl; v1.resize(7); cout<<v1.size(); v1.shrink_to_fit(); for(auto it=v1.begin(); it!=v1.end(); it++) cout<<*it; return 0; }

Is it correct one

it works with no datatype errors

Nah still not worrking