Develop front-end software.

I wouldn't recommend doing Win32 development in C++ unless you're using Qt as a tool and if you don't know about Windows programming, Qt wouldn't be the right place to start... Try something like C#

#include<stdio.h> #include<math.h> int main() { float angle,sin,cos,tan; printf("enter an angle:/n"); scanf("%f",angle); //degree to radian// angle=angle*3.14/180; sin=sin(angle); cos=cos(angle); tan=tan(angle); printf("sin=%f cos=%f tan=%f\n",sin,cos,tan); return 0; }

whats wrong with this

whats wrong with this

Scanf

Scanf

Thank u

Why does c have so many vulnerable functions in the standard library? Like today I learned that basic functions like printf and scanf are vulnerable to format string exploits and buffer overflows. Why aren't these functions rewritten so they can be secure?

Ok

Hi guys, I have a question, I'm trying to save names in a string table in my "change" function (*array[]) The problem is as soon as I want to increase the index of the stringtable, the debugger reports a threat and the program crashes please help me... i know if i set the variable "c"= '\0' the programm doesnt crash..... but i dont get why... could someone please explain why... I am a beginner so please dont be that rude😅😆 funciton // void change(char input[], char *list[]){ char *array[60]; int name = 0; int counter = 0; int c; for(int index = 0; input[index] != '\0';index++){ if(input[index] != '\n'){ c = input[index]; *(* (array + name) +counter) = c; counter++; } if(input[index] == '\n'){ name++; counter = 0; } } } and my input for the function are these names:Gunther Pruschke Milica Mohaupt Hannelore Christoph Inga Stadelmann Semra Christoph Karina Tlustek Leonhard Nette Birgitt Textor Hans-Helmut Rosenow Stanislaw Hartmann Arzu Trüb Valerie Geisler Agnieszka Bauer Friedl Scholz Emanuel Gierschner Erdmute Schmidt Carmela Sölzer Saskia Segebahn Karl-Wilhelm Kabus Gerda Heinrich Diethelm Heser Francesca Dörschner Horst-Dieter Geisler Fabian Rörricht Gero Speer Jann van der Dussen Waltrud Heinrich Friedl Losekann Nikola Oestrovsky Dennis Höfig-Klapp Ada Kraushaar Desiree Schäfer Silvana Hartmann Concetta Naser Tino Matthäi-Römer Maxim Schuchhardt Uschi Hauffer Rosel Klapp Brit Stahr Otto Bruder Käte Schmiedecke-Schleich Karl-Heinrich Kade Bettina Dobes Natalja Tröst-Thies Hartwig Scholz Dörte Ritter-Riehl Christa-Maria Spieß Ernst Adolph Jakob Segebahn Eva-Marie Stadelmann Cläre Scholz-Blümel Editha Hecker Denny Schuchhardt-Eberhardt Cordula Scholtz Jolanda Käster Dieter Hertrampf Catherine Ruppert Nikola Bärer-Tlustek Ioannis Mielcarek Henrik Rudolph

Why does c have so many vulnerable functions in the standard library? Like today I learned that basic functions like printf and scanf are vulnerable to format string exploits and buffer overflows. Why aren't these functions rewritten so they can be secure?

That function is unsafe if you didn't use it correctly

You can use max field width on both printf and scanf to limit buffer. Check what scanf return

But i prefer input string than convert it rather than check what scanf return

the scanf_s privated goods added by Microsoft

why is it unsafe? please explain

lol

#pragma warning(disable : 4996)

what's the point of using x & 0xFFFFFFFF in code? doesn't it just leave the bits as is? or am i missing something

I think it should be understood in combination with the actual code

what's the point of using x & 0xFFFFFFFF in code? doesn't it just leave the bits as is? or am i missing something

depends on the type of 'x', if it's larger than 32 bit, it doesn't leave them as is

depends on the type of 'x', if it's larger than 32 bit, it doesn't leave them as is

does it trim them?

I remember this operation can be derived to find out how many 1s there are in the binary of a number

using the & and |

ok guys i am more confused right now😂😅

does it trim them?

well, you're esentially cutting out every bit that is set in FFFFFFFF

I remember this operation can be derived to find out how many 1s there are in the binary of a number

it's a terrible idea to implement this yourself, use std::popcount instead

I think it should be understood in combination with the actual code

well i actually saw this in context of python code but i thought i'd post it here since a c++ chat might be more acquaint with bit operations

In fact, many things are very bad to realize by themselves

But I think it's also a good way to exercise ur thinking, not to build wheels repeatedly. lol

well i actually saw this in context of python code but i thought i'd post it here since a c++ chat might be more acquaint with bit operations

i saw it in combination with bitshifts (x << (32-n)) & 0xFFFFFFFF or here x0 = x & 0xFF x1 = (x>>8) & 0xFF x2 = (x>>16) & 0xFF x3 = (x>>24) & 0xFF

In fact, many things are very bad to realize by themselves

in this case especially, you're making it much harder for the compiler to optimize your code. there are cpu architectures that implement popcount as a instruction, lookup "nsa instruction" if you want to read up on some funny trivia :D

i saw it in combination with bitshifts (x << (32-n)) & 0xFFFFFFFF or here x0 = x & 0xFF x1 = (x>>8) & 0xFF x2 = (x>>16) & 0xFF x3 = (x>>24) & 0xFF

i guess it does in fact in case of & 0xFF just set bits after the 8th position to zero

i guess it does in fact in case of & 0xFF just set bits after the 8th position to zero

well the second example just accesses the individual bytes, in c/++ you might aswell use a union for that

okk

well the second example just accesses the individual bytes, in c/++ you might aswell use a union for that

true

okay, i think i got it, thank you guys

bit operation is still used in the embedded direction, such as stm32

😢I don't want to deal with bit operators at all

bit operation is still used in the embedded direction, such as stm32

i'm reverse engineering a mangled proprietary format so i need it a lot lol

lol

my major will be studied in the future, but I prefer software engineering

why is it unsafe? please explain

Buffer overflow, etc

the scanf_s privated goods added by Microsoft

That thing is non standard but you can use this libc https://github.com/rurban/safeclib

That's the thing, I don't need to "think" how the compiler initializes the memory. I can just ask, and I will know for a fact. In order to compile the code, I supposed the type was a char[16]. In this case, GCC will do exactly the same thing for any of the following pieces of code: 1) char x[16] = {0}; 2) char x[16] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; 3) char x[16]; memset(x, 0, sizeof(char[16])); And this is how GCC tells me it will do: xorl %eax, %eax The funny thing is why does it write that assembly instead of this: mov eax,0x0 Apparently, the xor code is faster than the mov one, and that's what GCC will do when you use the -O3 switch.

Also in gcc you can fill array like 4) char x[16] = { [0 … 15] = 0 };

Also in gcc you can fill array like 4) char x[16] = { [0 … 15] = 0 };

You don't need it tho, If you initialize only few of array member, the rest will automatically initialized to zero

Except for the memset , I agree that could be an alternate

You don't need it tho, If you initialize only few of array member, the rest will automatically initialized to zero

In this case yes! But it can become a useful thing when you need to initialize some parts of array, for example first half of array will be ‘A’, and second will be ‘B’ char x[100] = { [ 0 … 49 ] = ‘A’, [ 50 … 99 ] = ‘B’ };

Hi there. I hope someone will tell. How to find the smallest number of an array from the end? I wrote the code but the location of the item is not determined correctly

Hi there. I hope someone will tell. How to find the smallest number of an array from the end? I wrote the code but the location of the item is not determined correctly

Share the code

Share the code

https://onlinegdb.com/hrzfGT6y4

Also, Consider change your array. Variable length array is slow and dangerous. It could lead to Stack Overflow

Also, Consider change your array. Variable length array is slow and dangerous. It could lead to Stack Overflow

I'm sorry but your message is off can you write it again?

It is my task

It is short what I want smallest=arr[0][0]; for(i=m-1; i>0;i--) { for(j=n-1;j>0;j--){ if(smallest>arr[i][j]) { smallest=arr[i][j]; smallrowloc=i; smallcolumnloc=j; } } } printf("Smallest element in array is %d in location arr[%d][%d]\n", smallest, smallrowloc, smallcolumnloc); return 0; }

Hi there. I hope someone will tell. How to find the smallest number of an array from the end? I wrote the code but the location of the item is not determined correctly

Uhm, I got correct output. What's your input ?

Uhm, I got correct output. What's your input ?

2row 3 columns 4 5 4 7 6 8 My output largest 8 [1][2] Smallest 4 [3245][-64578] This location Ritht is [0][2]

2row 3 columns 4 5 4 7 6 8 My output largest 8 [1][2] Smallest 4 [3245][-64578] This location Ritht is [0][2]

Nope, I got Enter number of row and column: 2 3 Enter arr[0][0]: 4 5 4 Enter arr[0][1]: Enter arr[0][2]: Enter arr[1][0]: 7 6 8 Enter arr[1][1]: Enter arr[1][2]: Entered 2D Array: 4 5 4 7 6 8 Largest element in array is 8 in location arr[1][2] Largest element in array is 8 in location arr[1][2] Smallest element in array is 4 in location arr[0][0]

Maybe your program doesn't goes intro branch, main.c: In function ‘main’: main.c:75:3: warning: ‘smallcolumnloc’ may be used uninitialized in this function [-Wmaybe-uninitialized] 75 | printf("Smallest element in array is %d in location arr[%d][%d]\n", | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 76 | smallest, smallrowloc, smallcolumnloc); | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:75:3: warning: ‘smallrowloc’ may be used uninitialized in this function [-Wmaybe-uninitialized] main.c:73:3: warning: ‘largcolumnloc’ may be used uninitialized in this function [-Wmaybe-uninitialized] 73 | printf("Largest element in array is %d in location arr[%d][%d]\n", | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 74 | largest, largrowloc, largcolumnloc); | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:73:3: warning: ‘largrowloc’ may be used uninitialized in this function [-Wmaybe-uninitialized]

Nope, I got Enter number of row and column: 2 3 Enter arr[0][0]: 4 5 4 Enter arr[0][1]: Enter arr[0][2]: Enter arr[1][0]: 7 6 8 Enter arr[1][1]: Enter arr[1][2]: Entered 2D Array: 4 5 4 7 6 8 Largest element in array is 8 in location arr[1][2] Largest element in array is 8 in location arr[1][2] Smallest element in array is 4 in location arr[0][0]

Well, you did not change anything in the code? Because my way out is not like that. Why I do not know. Ty even with [0] [0] is not very suitable for me because I need to find the smallest from the end, ie in my case it is the second 4

Well, you did not change anything in the code? Because my way out is not like that. Why I do not know. Ty even with [0] [0] is not very suitable for me because I need to find the smallest from the end, ie in my case it is the second 4

Nope

Explain array of structure with example

Explain array of structure with example

struct sr { //code } struct sr arr[x]

Ok were is example

Ok were is example

That code was an example

Don't understand

Maybe your program doesn't goes intro branch, main.c: In function ‘main’: main.c:75:3: warning: ‘smallcolumnloc’ may be used uninitialized in this function [-Wmaybe-uninitialized] 75 | printf("Smallest element in array is %d in location arr[%d][%d]\n", | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 76 | smallest, smallrowloc, smallcolumnloc); | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:75:3: warning: ‘smallrowloc’ may be used uninitialized in this function [-Wmaybe-uninitialized] main.c:73:3: warning: ‘largcolumnloc’ may be used uninitialized in this function [-Wmaybe-uninitialized] 73 | printf("Largest element in array is %d in location arr[%d][%d]\n", | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 74 | largest, largrowloc, largcolumnloc); | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:73:3: warning: ‘largrowloc’ may be used uninitialized in this function [-Wmaybe-uninitialized]

I may have corrected. It's just that program worked, and now for some reason stopped working

I may have corrected. It's just that program worked, and now for some reason stopped working

😳 , Did compiler give you any messages ?

😳 , Did compiler give you any messages ?

No, it is not like turn off I mean that two day ago result was fine but know I have problems with location

No, it is not like turn off I mean that two day ago result was fine but know I have problems with location

Maybe if I start from the end I need to make not Smallrowloc=i; Maybe m-1 be better?

Hey, I have a question, whether it is necessary to allocate "size + 1" here at allocation of dynamic storage for a zero-character or simply "size" is enough? ... int size = strlen(someStr); char* s = new char[size]; or char char* s = new char[size + 1]; strcpy(s, someStr); 'cause it works in both cases...

Hi there. Maybe someone will help. I don't understand why my sum is not declared if I wrote a function for it. I hope for help https://onlinegdb.com/lxmHbiY1Pp

Hey, I have a question, whether it is necessary to allocate "size + 1" here at allocation of dynamic storage for a zero-character or simply "size" is enough? ... int size = strlen(someStr); char* s = new char[size]; or char char* s = new char[size + 1]; strcpy(s, someStr); 'cause it works in both cases...

+1 is used to store the null '\0' character which represents the end of c-style string and is useful in many use cases

+1 is used to store the null '\0' character which represents the end of c-style string and is useful in many use cases

thanks

Someone can help now?

Someone can help now?

I have one problem with code in C

you wrote suma not sum

you wrote suma not sum

If you me?Thanks, but I have already solved that problem. Now I am faced with the fact that the code does not do what is needed. This code don't make sorting. But I think it everything was correct

how to write simple quadratic c program???

how to write simple quadratic c program???

With your hands

hi your welcome

That thing is non standard but you can use this libc https://github.com/rurban/safeclib

I know

remove line 7