Well, I have a question. What is the difference between memory allocated using new and malloc. When I did new and then used realloc to the same memory, it gave me an error saying that I can only use realloc after malloc. Why? Memory is memory! Ain't that true?

malloc doesn't call a constructor

Constructor is the one that's invoked when the object is created right ?

Who can help me with my English exam tomorrow?

Why though? The Internet says that C is easier and that it will help me

If you what to be a C++ programmer, learn C++

Okay but I don't know where to start

Just start by programming! I don't know how often I have to repeat this but you only really learn C++ by WRITING projects in it. Set yourself a little goal and off you go!

Just start by programming! I don't know how often I have to repeat this but you only really learn C++ by WRITING projects in it. Set yourself a little goal and off you go!

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Is there any offtopic group?

hi i have some truble about how to remove spaces from a char* string but with the optimised way is there a sympatic guy how can help me pls?

in one or two lines

mmm are you sure about it

ah oke oke i think that what i wrote but yeah now i see how to compress it

Hi. I have few questions about functions. Kindly have a look at the below paste. https://pastebin.com/Mcykq0q4

In function_2, you are returning the address of local variable that will be popped out of stack after the function is finished.

Ya... Can u read the questions below the code?

A1: I am not 100% sure, but 0 returned by function_2() must be NULL (NULL equals 0). A2: You can return value but not the pointer. Because, values are copied. Even if, the object will be destroyed at the end of the function, its copy will still exist. A3: A2 is the answer for Q3, too

Two copies does not share the same memory. Just like in real life, your second duplicate car does not get crashed if you crash the first one.

Ya... Can u read the questions below the code?

Ok I understand so far. But where does it copy resides I mean which memory segment? Since stack frame got deleted for that function.

It first returns by value, and then take the memory of local variables. Returned copy value will have it is own stack mem inside the scope of caller of the function_2()

funtion_2 returns address of local, it's UB. In fact most likely will not be NULL

So getting 0 (NULL) I must be lucky 😂

It's just compiler behaviour with given flags. Try -O3

If in short, new also calls a constructor for you. But you can't just replace new with malloc and placement new because then you would need to also call destructor explicitly and use free. I mean, never mix new and free, malloc and delete

So during this period returning from callee to caller does it stores in a register or something?

malloc doesn't call a constructor

What makes you say new calls constructor?

Idk. You don't have to think this low-level in high-level language like C. It just copies the value to new location, then destroys the old value

hi a small question pls, how can i return -1 if a char* string is empty

Ok I understand so far. But where does it copy resides I mean which memory segment? Since stack frame got deleted for that function.

In your case it's most probably in register.

What makes you say new calls constructor?

Use if Statement like if(strcmp(string, '\0') == 0){ return -1} I don't remember correctly I think strcmp returns 0 when matches. Google to confirm. Btw your function must be of a int return type.

Just start by programming! I don't know how often I have to repeat this but you only really learn C++ by WRITING projects in it. Set yourself a little goal and off you go!

strcmp compare two string if they are equal it return 0

so it doesn't work i wrote smthg like this and it doesnt work too if(str==NULL){ printf("test : %s\n",str ); return -1;

hi a small question pls, how can i return -1 if a char* string is empty

so it doesn't work i wrote smthg like this and it doesnt work too if(str==NULL){ printf("test : %s\n",str ); return -1;

so it doesn't work i wrote smthg like this and it doesnt work too if(str==NULL){ printf("test : %s\n",str ); return -1;

Just kidding

Try if(!str || !*str)

Nerd 👍

new and operator new are different things