yeah that's better but in C++11 and more that's not recommended

yeah that's better but in C++11 and more that's not recommended

> so many bugs What ?

because that's C way to doing things C++ is OOP to make things easier for programmer C is not OOP so it's harder to code on it but it is a bit faster in runtime

char* is good but so many bugs could bring with your code (it's hard to be controlled as it isn't an object with constructor and deconstructor)

No, I mean. What's the cons that using const char * than std::string for string that didn't changed at runtime ?

He's saying const char* not char* = new char[] Basically pointing to the read-only string literal pool in the memory.

He's saying const char* not char* = new char[] Basically pointing to the read-only string literal pool in the memory.

I'm not so expert but I know that std::string has these things that const char * doesn't 1-it has 3 iterator but const char * only has one pointer (so sizeof(std::string) == 3*sizeof(const char *)) 2-it allocates more than what is in use (it's bad as you said it won't be changed in runtime) 3-it has simpler interface (it's an class with constructor and deconstructor no need to new and delete[])

I'm not so expert but I know that std::string has these things that const char * doesn't 1-it has 3 iterator but const char * only has one pointer (so sizeof(std::string) == 3*sizeof(const char *)) 2-it allocates more than what is in use (it's bad as you said it won't be changed in runtime) 3-it has simpler interface (it's an class with constructor and deconstructor no need to new and delete[])

www.learncpp.com Good one

I'm learning C++ for 4 years but I still feel I don't know nothing

Try building real applications. Contribute to open source projects that will help

don't blame me for 1st that it's only 16Byte more (in my pc) it is sometimes important to have something as small as you can

const char * allocation is on data segment. It's much faster because std::string allocation is on heap. heap is heavier and need to catch error if coudn't allocate memory from heap.

you should put unconditioned break in your switch

const char * allocation is on data segment. It's much faster because std::string allocation is on heap. heap is heavier and need to catch error if coudn't allocate memory from heap.

Wrong. const char * is not an allocation, it does not even imply that the data lives in .data section. const char * simply says: You can't write to memory via this pointer. const here is just a compile time check that validates: a dereference only works for reading.

It it lived on .rodata ? 🤔

It can live everywhere.

Wrong. const char * is not an allocation, it does not even imply that the data lives in .data section. const char * simply says: You can't write to memory via this pointer. const here is just a compile time check that validates: a dereference only works for reading.

So why char *str = "defined string" in C++1 need to implicitly declare it with const word ?

the compiler may optimize I guess

Because that string literal is read only, so it does not make any sense to write via that pointer

optimize what?

Because that string literal is read only, so it does not make any sense to write via that pointer

So where the string literal live ?

So where the string literal live ?

in that example it can live in .rodata, but that does not prove anything about your const char * statement

I do believe this is compiler implementation details. but usually it's in the text/code segment.

that string is not necessary to be executable, so placing it on .text section is an not ideal thing to do, but yes .text is read only by its nature

> size of an array should be know at compile time. Because it's using defined variable, it's not a VLA. Even though the output of -E isn't expanded.

VLA?

Variable length array

So is okay to use variables as length

I will use macro but this is fine size _t sz = 100 type arr[sz] Compile with clang++ with -pedantic-errors no warn/errors

Variable length array

I will use macro but this is fine size _t sz = 100 type arr[sz] Compile with clang++ with -pedantic-errors no warn/errors

What is that?

You can't use std::begin() and std::end() on it

C-style arrays should be avoided all together

cpp is powerful 😕

yeda

hi iman

Hi daz

فارسی شد؟

C-style arrays and C-style strings are faster and more efficient than std ones

C-style arrays and C-style strings are faster and more efficient than std ones

the homework is: Write a program where two different queue structures use the same array. The first of the queues you will write will try to use the array from beginning to end, while the second will use it from the end to the beginning. Do not forget that queues may conflict and create a mechanism to prevent this. One queue may use more space in the array than the other queue.

What is that?

int a; //input a; int arr[a]; This is variable length array

hi...I'm a biginner(c++). Am trying to reverse all the characters of a sentence...plz anyone help me to correct the errors. #include <iostream> using namespace std; int main(){ cout<<"\n\nInput your message : "; int size=100; char string[size]; cin>>string; char rev_string[100]; int j = 0; for (int i = 100; i < 0; i--){ while(string[j] =! NULL){ string[j] = rev_string[i]; j++; }break; }cout<<rev_string; return 0; }