oh i see

thank you so much

os give you the number but convert it into ascii character

god, I swear I'm wrong somewhere, I feel it. Correct me, if I'm mistaken.

now it makes sense thanks

no i dont think so u are correct

oh i see

read about arithmetic of pointers in c++.

i mean u r correct lol

sure

if i use "using namespace std" does it take extra memory or not?

if i use "using namespace std" does it take extra memory or not?

No

It doesn't affect the compiled code

It doesn't affect the compiled code

okay, got it

But it's still a bad idea to use it

why?

why?

I could explain but it's a really well-documented problem. I suggested you search

I could explain but it's a really well-documented problem. I suggested you search

aha i will

hi, i would like to ask, does the sleep() function causes busy waiting when used inside a thread, i need a function like sleep but that doesnt block the threads

hi, i would like to ask, does the sleep() function causes busy waiting when used inside a thread, i need a function like sleep but that doesnt block the threads

> like sleep but that doesnt block the threads Do you understand that it is 2 opposite things?

> like sleep but that doesnt block the threads Do you understand that it is 2 opposite things?

i mean, i only need to block 1 thread

while the others keep running

i mean, i only need to block 1 thread

So what's the problem?

i mean, i only need to block 1 thread

sleep() blocks the thread caller not the process caller so don’t worry

use it normally

i tought, sleep, is like doing something like while(true), that blocks everything

i tought, sleep, is like doing something like while(true), that blocks everything

it blocks the thread

i tought, sleep, is like doing something like while(true), that blocks everything

While true doesn't block everything

not the process

While true doesn't block everything

i mean if you use while(true) inside a thread, the other threads have to wait, and it consumes cpu power, i could do a sleep function like for(int i = 0 ; i<100000;i++){} to block the thread for a current amount of time, but that would cause busy waiting, so i was wondering if the sleep function uses the same principle but i think no, thanks

Anyone help me with crafting udp packet, i need to send udp packet with custom IP source header

i mean if you use while(true) inside a thread, the other threads have to wait, and it consumes cpu power, i could do a sleep function like for(int i = 0 ; i<100000;i++){} to block the thread for a current amount of time, but that would cause busy waiting, so i was wondering if the sleep function uses the same principle but i think no, thanks

> the other threads have to wait Why?

i mean if you use while(true) inside a thread, the other threads have to wait, and it consumes cpu power, i could do a sleep function like for(int i = 0 ; i<100000;i++){} to block the thread for a current amount of time, but that would cause busy waiting, so i was wondering if the sleep function uses the same principle but i think no, thanks

no. the sleep function is actually a syscall; a function supported by your operating system. when you call sleep(), the scheduler will move your thread from running state to blocking state, and move it back to ready state once the time you specified has been passed. only once your thread is back to the ready queue, the scheduler can schedule it

i mean if you use while(true) inside a thread, the other threads have to wait, and it consumes cpu power, i could do a sleep function like for(int i = 0 ; i<100000;i++){} to block the thread for a current amount of time, but that would cause busy waiting, so i was wondering if the sleep function uses the same principle but i think no, thanks

other threads don't have to wait, user threads are usually preemptable; the scheduler may reschedule them at any given moment. it's still a waste of cpu time tho

no. the sleep function is actually a syscall; a function supported by your operating system. when you call sleep(), the scheduler will move your thread from running state to blocking state, and move it back to ready state once the time you specified has been passed. only once your thread is back to the ready queue, the scheduler can schedule it

thanks, my doubts where on this

> the other threads have to wait Why?

sorry i got wrong, i went confused

> the other threads have to wait Why?

i meant this https://pastebin.pl/view/d67f54f7 , the output usually is not uniform but a thread occupies it

i meant this https://pastebin.pl/view/d67f54f7 , the output usually is not uniform but a thread occupies it

I can see both: thread 1 and thread 2 in the output

I can see both: thread 1 and thread 2 in the output

yes, but was expecting something like Thread1 Thread2 Thread1 Thread1, or to be generally uniform

yes, but was expecting something like Thread1 Thread2 Thread1 Thread1, or to be generally uniform

depends on the scheduler (your os)

depends on the scheduler (your os)

thanks, i have things more clear now

yes, but was expecting something like Thread1 Thread2 Thread1 Thread1, or to be generally uniform

They both are printing output to stdout. But it won't fair in order Thread1, Thread2, Thread1... You need to use semaphore for that.

They both are printing output to stdout. But it won't fair in order Thread1, Thread2, Thread1... You need to use semaphore for that.

not necessarily a semaphore. there are other synchronization methods that he can use in this case

since he wants 1 per 1, maybe a condition will be better

since he wants 1 per 1, maybe a condition will be better

Yeah an atomic conditional variable should be enough. That looks a binary semaphore to me.

i mean if you use while(true) inside a thread, the other threads have to wait, and it consumes cpu power, i could do a sleep function like for(int i = 0 ; i<100000;i++){} to block the thread for a current amount of time, but that would cause busy waiting, so i was wondering if the sleep function uses the same principle but i think no, thanks

You may take a look at rep; nop;, it's pause. (If you use x86 family).

PAUSE Improves the performance of spin-wait loops. When executing a “spin-wait loop,” processors will suffer a severe performance penalty when exiting the loop because it detects a possible memory order violation. The PAUSE instruction provides a hint to the processor that the code sequence is a spin-wait loop. The processor uses this hint to avoid the memory order violation in most situations, which greatly improves processor performance. For this reason, it is recommended that a PAUSE instruction be placed in all spin-wait loops. An additional function of the PAUSE instruction is to reduce the power consumed by a processor while executing a spin loop. A processor can execute a spin-wait loop extremely quickly, causing the processor to consume a lot of power while it waits for the resource it is spinning on to become available. Inserting a pause instruction in a spin-wait loop greatly reduces the processor’s power consumption. This instruction was introduced in the Pentium 4 processors, but is backward compatible with all IA-32 processors. In earlier IA-32 processors, the PAUSE instruction operates like a NOP instruction. The Pentium 4 and Intel Xeon processors implement the PAUSE instruction as a delay. The delay is finite and can be zero for some processors. This instruction does not change the architectural state of the processor (that is, it performs essentially a delaying no-op operation).

https://godbolt.org/z/z8ceGP7v5

Another thing is that, use pthread_cond_wait. It will make your program sleep until conditional variable is satisfied and signaled. But because your program sleeps, you may get greater latency (it is better than spinning if your threads are expected to have many contentions).

anyway google titles either "significance of (void*) -1" or "Is ((void *) -1) a valid address?"

gotcha it is basically 0xffffffff

gotcha it is basically 0xffffffff

ok)

Is it C/C++ question?

Calculate the student's GPA for the semester using C++ program. The program should be able to accept a student's name, matriculation number and number of course he/she is taking for that semester. Then for each course the following data is needed. • The course number a string eg. EEE311 •course credit "an integer" •grade received for the course "a character" Please help me

Calculate the student's GPA for the semester using C++ program. The program should be able to accept a student's name, matriculation number and number of course he/she is taking for that semester. Then for each course the following data is needed. • The course number a string eg. EEE311 •course credit "an integer" •grade received for the course "a character" Please help me

show you code, where are you stuck ?

👍

Calculate the student's GPA for the semester using C++ program. The program should be able to accept a student's name, matriculation number and number of course he/she is taking for that semester. Then for each course the following data is needed. • The course number a string eg. EEE311 •course credit "an integer" •grade received for the course "a character" Please help me

You want us to write code for you?

You want us to write code for you?

it seems so

hey guys anyone knows how to do while loop that it will end if the user enter zero?

hey guys anyone knows how to do while loop that it will end if the user enter zero?

Nope

hey guys anyone knows how to do while loop that it will end if the user enter zero?

while (event != 0) { ... }

int count =0; do { int num; Console.Write("Enter a number: "); num=Convert.ToInt32(Console.ReadLine()); count++; }while (event!=0); what is my mistake with this bro?

event is a placeholder. You should evaluate 'num' as it's the user input and what you want to use to make the 0 = exit condition

Print the value 333.546372 in a field width of 15 characters with precisions of 1,2,3,4 and 5.

int count =0; do { int num; Console.Write("Enter a number: "); num=Convert.ToInt32(Console.ReadLine()); count++; }while (event!=0); what is my mistake with this bro?

/warn offtop

Print the value 333.546372 in a field width of 15 characters with precisions of 1,2,3,4 and 5.

#include<stdio.h> void main() {//Question 2 B.i float a=123.4567; printf("%.2f\n",a); //Question 2 B.ii float b=3.14159; printf("%.3f\n",b); //Question 3 B.iii printf("%-15.1f\n",333.546372); printf("%-15.2f\n",333.546372); printf("%-15.3f\n",333.546372); printf("%-15.4f\n",333.546372); printf("%-15.5f\n",333.546372); } Return 0;

/warn offtop

offtop?

offtop?

It is not C++

offtop?

Looks like C#

Ah, shi.. right, didn't notice it

it C# hope you guys dont mind me asking about it bro Im very new to programing

it C# hope you guys dont mind me asking about it bro Im very new to programing

Dude, read the rules

What the fuck is that

it C# hope you guys dont mind me asking about it bro Im very new to programing

this is c/c++ group

Before diving into some complex stuff, learn basic syntax

what do you want the lambda to do

auto lambdaSunstract = [](double a, double b) { return a - b; }; double c = lambdaSunstract(10.0, 5.0);

std::function<double(double, double> sub = [](double a, double b){ return b - a}

this is the simple syntax

std::function<double(double, double> sub = [](double a, double b){ return b - a}

You don't have to assign it to std::function by the way, you can keep it as lambda type with auto

You don't have to assign it to std::function by the way, you can keep it as lambda type with auto

yes I know

just showing him the syntax.