string* ptrvalue = new string[2]; ptrvalue[0] = "bool"; ptrvalue[1] = "char"; for (int i = 0; i < 2; i++) { cout << sizeof(ptrvalue[i]); } This is how I always define str and I need bool, int

string* ptrvalue = new string[2]; ptrvalue[0] = "bool"; ptrvalue[1] = "char"; for (int i = 0; i < 2; i++) { cout << sizeof(ptrvalue[i]); } This is how I always define str and I need bool, int

wait... are you trying to get the sizeof a type inside a string?!

I don't understand what you are trying to get. Could you please elaborate further what you mean by "I need bool, int"?

+

I think he's trying to get sizeof a type, where the type name is inside the string

#include<iostream> using namespace std; int main() { cout << 2.5F * 2U + 3LU * 5U - ‘b’<< endl; cout<<sizeof (2.5F * 2U + 3LU * 5U - ‘b’) return 0; }

How to fix this code

How to fix this code

The first cout ('b')

How to fix this code

cout << 2.5F * 2U + 3LU * 5U - ‘b’<< endl;

I mean this one

next fix would be to stop using that namespace, then maybe commenting what that code is even supposed to do.... and maybe not using endl just for one line if you are ending the program anyway

#include<iostream> using namespace std; int main() { int a = 3, n = 4; a %= n %= 4; cout << a << ' ' << n << endl; return 0; }

#include<iostream> using namespace std; int main() { int a = 3, n = 4; a %= n %= 4; cout << a << ' ' << n << endl; return 0; }

Hey bro why are you use % symbol

x %= y is same as x = x % y

modulo operator

#include<iostream> using namespace std; int main() { int a = 3, n = 4; a %= n %= 4; cout << a << ' ' << n << endl; return 0; }

arr = realloc(arr, sizeof(*arr) * (--n)); Is there anything wrong in this? I must work as expected right? I am just shrinking the memory allocated by one unit of whatever datatype a *(arr + i) is

From the size itself, I don't see something weird, but who knows?, the code is incomplete, can't review what might go wrong here. nit: realloc() should use a temporary variable to handle the failure case, otherwise you're leaking memory when the allocation fails, because you lose the old pointer. void *tmp; tmp = realloc(arr, new_size); if (!tmp) { // handle failure // arr must be freed somewhere // tmp is null return ...; } arr = tmp; // arr is resized here..

why void *tmp instead of whatever the type of arr is

Better be whatever the type is, but void * can be assigned to any other pointer types without cast (in C). It's not an excuse to use void *, I just don't know what the type of arr.

How to invoke python script by c++ ? Please give me some examples. Thanks 👍

How to invoke python script by c++ ? Please give me some examples. Thanks 👍

guys, what is the error? int x = 5; int *px = *(x-1); can't get the value (x-1) or what?

this is a task, we need to find mistakes and fix them

What program should do? Get value x-1?

set pointer address to x-1

it's a segmentation fault

Try this int x = 5, *px = *(&x)-1; Still don’t understand why do you need pointer for this :)

Isn't this wrong? Because you're storing int in int*

Yes, but physically it is not wrong. Integer value is same size as integer pointer, and integer pointer is a memory cell too. We can use it as a common integer value, or store addresses in integer type.

1. They might not be the same size 2. It's an error without explicit casting 3. Why not just do x-1 then?

1. Agree, I told about most popular x86 platform 2. I am using C, and I haven’t got any error. Maybe something wrong with my compiler? 3. I don’t know. I thought this guy want to calculate x-1 using pointer’s operations and just put it into pointer.

Ah it's only an error in C++. In C, it just shows a warning.

Yes, but physically it is not wrong. Integer value is same size as integer pointer, and integer pointer is a memory cell too. We can use it as a common integer value, or store addresses in integer type.

like you want to create python module or... you want to literally run python process?

Check out polyglots like Metacall

yeah

Hi there. Wondering if anyone has any ideas about this I've been tasked with writing a file in one program and then reading it using another I have both programs working and sharing a file but after I would like to output a message that the file has no more characters in it when I'm reading it back out Is there a way to do this using the read() system call? I've had a look on Google but struggling to find a solution 👍

vector<string>ss; for(int i=0;i<n;i++) { cin.ignore(); string s; getline(cin,s); ss.push_back(s); } not working for input: n=2 4 5 why 5 is not being pushed to the vector?

can visual basic 6.0 code work on visual basic 2013? Please someone should help me out.

I think using write() with fd number 1 to write to stdout

I am afraid you have not messaged the right group

can visual basic 6.0 code work on visual basic 2013? Please someone should help me out.

This is not a relevant question for this group. Please refrain from asking questions unrelated to the group. The answer to your question is no. VB6 requires a VB6 runtime while VB.Net requires the .Net CLR. The runtime libraries are different for both and are not compatible.

Let's wait and see. Perhaps someone might answer me.

Hi guys, I am looking for some advice here cause I really don't know how to move: I am asked to fill a possibily very huge matrix with 0s and 1s. The problem is, the more this matrix grows, the more memory those 1s and 0s will occupy. So the first thing I said was "fine, I shall use unsigned shorts in order to represent 0s and 1s, as a whole int seems unnecessary"; then I thought "what about actually creating a binary number, which takes only 1 bit in memory?"... this way, I would optimize the memory occupation of the matrix, but I don't know how to do that. Do you have any suggestions? Sadly, I do not have any code, because other than using a bit mask I haven't come up with anything useful (note, I just started C programming, therefore I am no real expert, but feel free to give me, if you are willing to, as much complex code as you want, I'll try to figure it out by myself later on)... thanks!