omike1900 you can not include any library, just like this
void update(int *a,int *b) { int sum = *a + *b; int absDifference = *a - *b > 0 ? *a - *b : -(*a - *b); *a = sum; *b = absDifference; }
Aitabhi I like your use of ternary operators in the above code.Likes!!
viriyamt [deleted]
rettoproddem [deleted]rettoproddem [deleted]rettoproddem [deleted]decoder_ why do we need to assign it to some variable?
hhpkoop because if you overwrite a, you can't calculate b, btw the "absDifference" is unnecessary
krmld void update(int *a,int *b) { *a += *b; *b = 2*(*b) - (*a); *b = *b > 0 ? *b : -1*(*b); }
Yes, you can!
Red_Arrow why u have multiplied 2 ?
edgardo_muniz It is a way of adjusting the value in *a after the sum. I will try to explain in a simple way.
*a += *b; //a becomes a+b *b = 2*(*b) - (*a); //a+b -b-b = a-b *b = *b > 0 ? *b : -1*(*b); //make positive if b is negative.
NOTE: in the comments I omit the * and change the order of the different in order to make it easier to see. I assume you can understand what it is doing.
Hope this helped.
dafnis clever, but i think this would confuse someone with bad math
benaffleks Very smart use of 2* to negate the previous *a sum!
sagarakbari17 YOU CAN DO THIS
int temp=*a;
*a=*a+*b;
if((temp)>(*b)) (*b)=(temp)-(*b); else (*b)=(*b)-(temp);ankit_mishraa121 [deleted]
marcus_wong930 yep. i use int t to store *a so that it wont be lost
abhishekkumar_ab [spoiler] because,we r printing it on the main function [/spoiler]
SudhanshuMohan or u can simply use "abs" which is in math.h header file
pablosax27 why so much complication, just #include cmath *a = *a + b; *b = abs(*a - *b - *b);
satiish4228 Good Code
rakshanihamad Why we need a if else?
Vishal__Roy since we have to find absolute difference. We need to use if else statement to eliminate -ve value.
manojkumarnov23 can you explain what it does?
samarthchadda_i1 u r genius
jack_rabo why not including it? abs(*a-*b) is much more agile. there is no rules against the use of headers (be them or ) on this exercise. for what i know your code is much more resource consuming in terms of logical operations (i.e. processor cycles) than the use of a simple function provided by an useful header. cheers
pablosax27 agree!!!!
kunal_tyagi very well use of ternary operator !!
amark720 thanks bro for the help!!!
whitlock_kc I included cmath and got full points.
giantmalik Can i get more problems related to pointers? i want some more to improve pointers.
giantmalik ????
doctr_kz ?????????????????????????????????????????????????
trevorlang_trev1 !!!!!!!!!!!!!!!!!!!!
CHODHARY include
/* * * Prosen Ghosh * American International University - Bangladesh (AIUB) * */ void update(int *a,int *b) { // Complete this function int aa = *a; *a = *a+*b; *b = aa-*b; if(*b < 0)*b *= -1; } int main() {
int a, b; int *pa = &a, *pb = &b; scanf("%d %d", &a, &b); update(pa, pb); printf("%d\n%d", a, b); return 0;}
CHODHARY void update(int *a,int *b) { // Complete this function int aa = *a; *a = *a+*b; *b = aa-*b; if(*b < 0)*b *= -1; } int main() {
int a, b; int *pa = &a, *pb = &b; scanf("%d %d", &a, &b); update(pa, pb); printf("%d\n%d", a, b); return 0;}
pablosax27 I was on the dark side of pointers too but I just figured it out. For this problem think it as this: int sum = *a +*b; //it stores the value of *a + *b into sum but leaves the value of *a and *b the same int dif = abs(*a - *b); //same as before at this point, *a = *a && *b = *b && sum = *a + *b && dif = *a - *b (positive because of abs) now, to chage the value of the address of *a and *b you declare *a = sum; b = dif; now a & *b have new values Did it helped??? sivaraam's solution is the best so far. There is no need of if statements or nothing. Just add cmath, iostream, and std. This will make your code cleaner which is the best practice!!
nofmxc I would love more simple pointer problems also.
sivaraam My Solution
#include <stdio.h> #include <stdlib.h> void update(int *a,int *b) { // Complete this function *a = *a + *b; *b =abs(*a - *b -*b); } int main() { int a, b; int *pa = &a, *pb = &b; scanf("%d %d", &a, &b); update(pa, pb); printf("%d\n%d", a, b); return 0; }
udrulz92 why here using *b=abs(*a-*b-*b);why not *b=abs(*a-*b)?
gouravsingh096 what is abs ?
groverkg04 it is a function which is used to return the absolute or round off value of the parameter.
kunal_tyagi is this abs a pre-defined function in c++ ? in java it is pre-defined but in c and c++ ?
karthikrajagopal easy...
Muthukumar_T how void function return the value??
danielgcwik I got this error. But, It says I solved the challenge. solution.c: In function ‘update’: solution.c:7:9: warning: implicit declaration of function ‘abs’ [-Wimplicit-function-declaration] *b =abs(*a - *b -*b); // Complete this function is Abs traying to get the absolute value?
danielgcwik thnaks I used #include and got no error
frostymax4z what is the meaning of update dear
kunal_tyagi is this abs a pre-defined function in c++ ? in java it is pre-defined but in c and c++ ?
muditmehrotra991 you should include math.h library
baddulahemalatha kkk
Ethan13310 We don't want to use raw pointers in C++. We almost never use them, exept for interfacing with a C-written library. In this exercise, we should use references instead. But here's the solution:
#include <cmath> void update(int *a, int *b) { int tmp{*a + *b}; *b = std::abs(*a - *b); *a = tmp; }
And in real C++:
#include <cmath> void update(int &a, int &b) { int tmp{a + b}; b = std::abs(a - b); a = tmp; }
nisevi well you don't need to load a library for using abs nor an aditional variable:
*a = *a + *b; *b = *a - *b - *b; if (*b < 0){*b = *b * -1;}Ethan13310 Why do you want to reinvent the wheel ? The use of 'std::abs' is totally justified here and make the code shorter and clearer.
And by not using another variable, your code is absolutly incomprehensible.
nisevi [deleted]Ethan13310 Of course I understood you code, but it is unnecessarily complicated. With my code, we immediatly understand that 'a = a + b' and 'b = abs(a - b)'. But with your code, we have to do each calculation to understand what it is doing.
austino222 Don't be rude dude. Agreed with Ethan. Yes, you can demonstrate your grasp of pointer math here and that's laudable, but code written like this in production code will fail a code review. Don't re-invent the wheel and keep it simple!!
kunal_tyagi your code is simple and impressive. thankyou!
pedro_orellana_2 Totaly right
gkmamun void update(int *a,int *b) { *a = *a + *b; *b = *a - *b - *b;//here *a already changed into *a+*b; for this we have to write *b=*a-*b-*b if (*b < 0) {*b = *b * -1;} }
jpverma include
include
using namespace std;
void update(int *a,int *b) { // Complete this function
*a = *a + *b; *b = abs(*b - (*a-*b));}
int main() { int a, b; int *pa = &a, *pb = &b;
scanf("%d %d", &a, &b); update(pa, pb); printf("%d\n%d", a, b); return 0;}
congge just use *b = abs(*a- 2*b) because *a' = *a+*b ~
akshay_sankhyan1 what is the meaning of abs
Apocalipsis you mean *b = abs(*a-*b*2) Edit: Can't type two '*' at the same times
nithisingh *b=abs(*b-(*a-*b)); Please explain this statement.
nithisingh why this (*b-(*a-*b)); used?Why can't we simply type *b=abs(*a-*b);
skybee9925 (*b-(*a-*b)); -this removes the value of b that is added in the previous statement.
cl_nemesis #include <cmath> void update(int *a,int *b) { // Complete this function int suma = (*a) + (*b); int absolute=abs((*a)-(*b)); (*a)=suma; (*b)=absolute; }
cristian_archil1 good
thieugiatri4492 This is my code, please have some advice to optimize it
#include <stdio.h> #include <stdlib.h> void update(int *a,int *b) { // Complete this function int c=*a; *a = *a+*b; *b= (abs(c-*b)); } int main() { int a, b; int *pa = &a, *pb = &b; scanf("%d %d", &a, &b); update(pa, pb); printf("%d\n%d", a, b); return 0; }
thomascarmichae1 a simple solution:
#include <cmath> void update(int *a,int *b) { int temp = *a; *a = *a + *b; *b = abs(temp - *b); }
dvt32 #include < stdio.h > #include < stdlib.h > void update(int *a,int *b) { int temp = *a; (*a) = (*a) + (*b); (*b) = abs(temp-(*b)); } int main() { int a, b; int *pa = &a, *pb = &b; scanf("%d %d", &a, &b); update(pa, pb); printf("%d\n%d", a, b); return 0; }
ArgylePwnage Why use abs?
dvt32 [deleted]dvt32 Why not? (Not trying to be smart, I'm just curious).
ArgylePwnage I was just curious if you had a specific reason for doing it.
dvt32 According to the problem description:
b' = |a-b|
Hence why I use abs() to get the absolute value of a-b.
abobader4321 Why is it necessary in this case to redeclare *a as (temp) in order to let the abs() do it's job ?? Bcz I tried the following cood but it didn't work !!
include
include
include
using namespace std ;
void update(int *a, int *b) { *a = *a + *b ; *b = abs(*a-(*b)) ; } int main() { int a, b ; int *pa = &a, *pb = &b ;
cin >> a ; cin >> b ; update(pa, pb);cout << a << endl ; cout << b << endl ;
}
dvt32 Because after this line of code has been executed:
*a = *a + *b;
The value of 'a' has been changed.
And when the program reaches this line of code:
*b = abs(*a-(*b));
... you are using the new value of 'a', but you need its ORIGINAL value (hence why I store it in the variable 'temp').
jellybeanfiend We can also do *b = abs(*a - (2 * (*b))) to avoid the temp variable. Although perhaps that is less readable than using a temp variable. :D
eyeslife is it only the readbility the problem?
Prashantgang2305 This is a very simple problem which can be answered without using any extra library.
Namadu Sure, but if the abs function is already defined in stdlib.h, might as well use it there instead of rewriting the whole thing.
And sure, it's easy enough to do here. In general, though, I think it's good to get in the habit of using libraries rather than writing more code than needed.
sapthamaaleekaa why i am getting error if i use *b=abs(temp-(*b); instead of (*b) = abs(temp-(*b));
dvt32 It works fine both ways for me on Visual Studio 2015. What error are you getting?
sapthamaaleekaa Exactly!! The compiler in hackerrank is not accepting:-(
dvt32 I just tried it on HackerRank too - it works without the parantheses too. Can you show me the error message you're seeing?
darkestknight777 Can be done without extra variable too. :)
Rachel1985murray I'm new to c++ and thought this would be a good introduction but I don't understand how to get the absolute value are we expected to know the right syntax for it? I presume its something along the lines of abs(...) but have no idea of what way to use it (confused!)
Retro11231Asked to answer [deleted]twahlfeld A common thing to do is look to see if an abs function exists. However abs is such a trivial procedure you can either make a fuction/macro/conditionals to solve it ex:
#define abs(x) ((x) < 0 ? -(x) : (x))or
int abs(int x) { if(x < 0) { return -x; } else { return x; } }JLiersch Try to avoid the version using #define. This might lead to unexpected behaviour which will be hard to debug.
E.g.: int i = 0; cout << abs(++i) << endl;
This will print out 2 [!] using the #define version of abs.
twahlfeld Thanks for the heads up on that issue.
Felonious_Punk Can you please help me understand why that would output 2? 0 would first increment to 1, then go to the else clause of abs (resulting in 1) before entering the stream, wouldn't it?
JLiersch The preprocessor would replace each occurance of "abs(x)" by "((x) < 0 ? -(x) : (x))". Thus the code to be compiled would be:
int i = 0; cout << ((++i) < 0 ? -(++i) : (++i)) << endl;
This would lead i to be incremented twice. Once before checking if the conditional is true and the second time before evaluating the else clause.
ratedroy95 just make an if statement to check if it's lower than 0, then just multiply it by -1 to make it positive.
abdulaziz_raj you can just use #include '<'stdlib.h'>' and it will support the abs() function
fig31 just put an if statment in the function testing whether the value is less than 0, and if so multiple that value by -1. ex.
if(difference < 0) difference = difference * (-1);
problem solved!
Prashantgang2305 Use of preprocessor may give you unwanted results if not written with care.
See this link : http://stackoverflow.com/questions/1785572/why-should-one-bother-with-preprocessor-directives
Try doing without it.
jtate_nuim Have a look at this page http://www.cplusplus.com/reference/cstdlib/abs/
RaviSwami009 if(*b < 0) *b *= -1;
raisameneses You can always refer to the library before you start writing code. In C the absolute value is found in the #include library. eg. abs(yourNumber)
dtran18 You shouldn't need to use abs() function for this problem.
void update(int *a,int *b) {
int temp = *a; *a = *a + *b; //sum if (temp > *b) *b = temp - *b; //diff else if (*b > temp) *b = *b - temp; //diff}
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