did someone free?

#include <iostream> using namespace std; double add(double a, double b){ return a + b; } double sott(double a, double b){ return a - b; } double molt(double a, double b){ return a * b; } double divi(double a, double b){ return a / b; } int main(){ int Opr=0; double numero1; double numero2; double res; cout << " Addizione = 1\n Sottrazione = 2\n Moltiplicazione = 3\n Divisione = 4\n Che operazione vuoi eseguire?\n "; cin >> Opr; cout << "\n Qual'è il primo numero?\n"; cin >> numero1; cout << "\n Qual'è il secondo numero?\n"; cin >> numero2; res=(numero1, numero2); cout << "il risultato è " << res; } how can I set the operations whitout the switch? sry if the code is in italian

res=add(numero1, numero2); for the add, but how can i set that the user can decide the operation?

so there'arent any solutions without using the if, else and switch?

at least has a better malloc implementation tan GNU (...) it sucks

now you run your program with gcc and it runs twice as fast in benchmarks compared to MSVC

It's not fair comparison

how so?

double add(double a, double b){ return a + b; } double sott(double a, double b){ return a - b; } double molt(double a, double b){ return a * b; } double divi(double a, double b){ return a / b; } int main(){ int Opr=0; double numero1; double numero2; double res = 0; cout << " Addizione = 1\n Sottrazione = 2\n Moltiplicazione = 3\n Divisione = 4\n Che operazione vuoi eseguire?\n "; cin >> Opr; cout << "\n Qual'è il primo numero?\n"; cin >> numero1; cout << "\n Qual'è il secondo numero?\n"; cin >> numero2; if (Opr=1){ res=add(numero1, numero2); cout << "il risultato è " << res; }else {return 0;} if (Opr=2){ res=sott(numero1, numero2); cout << "il risultato è " << res; }else {return 0;} if (Opr=3){ res=molt(numero1, numero2); cout << "il risultato è " << res; }else {return 0;} if (Opr=4){ res=divi(numero1, numero2); cout << "il risultato è " << res; }else {return 0;} if (Opr>4){ cout << "impossibile! "; }else {return 0;} why in this way the compilator print all the operation?

double add(double a, double b){ return a + b; } double sott(double a, double b){ return a - b; } double molt(double a, double b){ return a * b; } double divi(double a, double b){ return a / b; } int main(){ int Opr=0; double numero1; double numero2; double res = 0; cout << " Addizione = 1\n Sottrazione = 2\n Moltiplicazione = 3\n Divisione = 4\n Che operazione vuoi eseguire?\n "; cin >> Opr; cout << "\n Qual'è il primo numero?\n"; cin >> numero1; cout << "\n Qual'è il secondo numero?\n"; cin >> numero2; if (Opr=1){ res=add(numero1, numero2); cout << "il risultato è " << res; }else {return 0;} if (Opr=2){ res=sott(numero1, numero2); cout << "il risultato è " << res; }else {return 0;} if (Opr=3){ res=molt(numero1, numero2); cout << "il risultato è " << res; }else {return 0;} if (Opr=4){ res=divi(numero1, numero2); cout << "il risultato è " << res; }else {return 0;} if (Opr>4){ cout << "impossibile! "; }else {return 0;} why in this way the compilator print all the operation?

double add(double a, double b){ return a + b; } double sott(double a, double b){ return a - b; } double molt(double a, double b){ return a * b; } double divi(double a, double b){ return a / b; } int main(){ int Opr=0; double numero1; double numero2; double res = 0; cout << " Addizione = 1\n Sottrazione = 2\n Moltiplicazione = 3\n Divisione = 4\n Che operazione vuoi eseguire?\n "; cin >> Opr; cout << "\n Qual'è il primo numero?\n"; cin >> numero1; cout << "\n Qual'è il secondo numero?\n"; cin >> numero2; if (Opr=1){ res=add(numero1, numero2); cout << "il risultato è " << res; }else {return 0;} if (Opr=2){ res=sott(numero1, numero2); cout << "il risultato è " << res; }else {return 0;} if (Opr=3){ res=molt(numero1, numero2); cout << "il risultato è " << res; }else {return 0;} if (Opr=4){ res=divi(numero1, numero2); cout << "il risultato è " << res; }else {return 0;} if (Opr>4){ cout << "impossibile! "; }else {return 0;} why in this way the compilator print all the operation?

Different os

now you run your program with gcc and it runs twice as fast in benchmarks compared to MSVC

oh.. it was trying to compute finbonacci sequence it is just computation on the same architecture nothing requires system calls also both on windows using mingw and MSVC

anyone help me with a c# code i m new to coding ....

C# is very different than C or C++

Guys where to study data structure and algorithm with c++

now you run your program with gcc and it runs twice as fast in benchmarks compared to MSVC

but GNU libc dont guarrantee the address returned by malloc

Guarantee what?

Guarantee what?

for pet proyects went nice, for production ones, is just a joke

Hey if anyone knows any project in c++ that we can do in one month and good for resume plz share

Can I DM you?

Guys where to study data structure and algorithm with c++

NOTES By default, Linux follows an optimistic memory allocation strategy. This means that when malloc() returns non-NULL there is no guarantee that the memory really is available. In case it turns out that the system is out of memory, one or more processes will be killed by the OOM killer. For more information, see the description of /proc/sys/vm/overcommit_memory and /proc/sys/vm/oom_adj in proc(5), and the Linux kernel source file Documentation/vm/overcommit-account- ing.rst.

NOTES By default, Linux follows an optimistic memory allocation strategy. This means that when malloc() returns non-NULL there is no guarantee that the memory really is available. In case it turns out that the system is out of memory, one or more processes will be killed by the OOM killer. For more information, see the description of /proc/sys/vm/overcommit_memory and /proc/sys/vm/oom_adj in proc(5), and the Linux kernel source file Documentation/vm/overcommit-account- ing.rst.

Also I read the exact article online it is misleading the person who wrote it didn’t clearly understand the bugs section when he read it “”” On Linux, there are no guarantees like those suggested above under MAP_NORESERVE. By default, any process can be killed at any moment when the system runs out of memory. “””

it says that if the process was killed mmap() will fail which is the function used by malloc

malloc is implemented by glibc not by the kernel malloc() calls sbrk() if the memory allocated is smaller than the provided memory page while mmap() is called if the memory allocated is larger sbrk() returns 0 on sucess and -1 on error mmap() returns an address to the mapped area and on failure it returns ( (void *) -1 ) both are handled correctly in case of an error and malloc will return

Also I read the exact article online it is misleading the person who wrote it didn’t clearly understand the bugs section when he read it “”” On Linux, there are no guarantees like those suggested above under MAP_NORESERVE. By default, any process can be killed at any moment when the system runs out of memory. “””

I talking about this line: By default, Linux follows an optimistic memory allocation strategy. This means that when malloc() returns non-NULL there is no guarantee that the memory really is available.

“”” By default, Linux follows an optimistic memory allocation strategy. This means that when malloc() returns non-NULL there is no guarantee that the memory really is available. In case it turns out that the system is out “””

still only if the system runs out of memory

Yes, but this makes irrelevant to check if malloc return an address or not

Yes, but this makes irrelevant to check if malloc return an address or not

Yes, but really nobody check malloc pointers

Thanks, I working on C89 for non stop fault tolerant systems. On this systems Guardian malloc's returned value don't follow the current GNU's behaviour. Is there any implementation of CPP polymorphic allocator for C89?

Thanks, I working on C89 for non stop fault tolerant systems. On this systems Guardian malloc's returned value don't follow the current GNU's behaviour. Is there any implementation of CPP polymorphic allocator for C89?

You can check o1heap on github Desc in readme O1heap is a highly deterministic constant-complexity memory allocator designed for hard real-time high-integrity embedded systems. The name stands for O(1) heap.

Thanks, I working on C89 for non stop fault tolerant systems. On this systems Guardian malloc's returned value don't follow the current GNU's behaviour. Is there any implementation of CPP polymorphic allocator for C89?

Thanks, I working on C89 for non stop fault tolerant systems. On this systems Guardian malloc's returned value don't follow the current GNU's behaviour. Is there any implementation of CPP polymorphic allocator for C89?

look this isn’t about malloc the same bug is mentioned in mmap() because malloc utilises it which is created by kernel devs not the gnu project and the bug you are talking about only applies if your process it hog most of the RAM on the entire computer which will be killed when you run it on all operating systems not just linux and will cause undefined behavior because it doesn’t matter anymore since you are getting killed anyway even before your programs crash or reads a buffer that hasn’t been allcoated

but this, makes check malloc's return irrelevant

to kill process a kill signal has to travel for few miliseconds and since basically the os gave up on your process mmap will return an invalid address for malloc that will point to a non-existant memory page that hasn’t been created yet for your program (because there isn’t enough RAM and space in the swap partition on the disk) so you might get a segfault if the kill signal arrived too late and your program read that invalid address or just your program will get killed first but your program will crash anyway so a segfault and kill signal or only a kill signal doesn’t matter since your program will fail anyway