iouyiugjl On Fri, Sep 10, 2010 at 5:00 PM, <algogeeks+nore...@googlegroups.com<algogeeks%2bnore...@googlegroups.com> > wrote:
> Today's Topic Summary > > Group: http://groups.google.com/group/algogeeks/topics > > - Explain <#12afb697e122ca05_group_thread_0> [8 Updates] > - I want improve my algorithm?? <#12afb697e122ca05_group_thread_1> [2 > Updates] > - how we can access 2nd element of an > struct<#12afb697e122ca05_group_thread_2>[3 Updates] > - Graphs... <#12afb697e122ca05_group_thread_3> [1 Update] > - Recursion!!!!!!!!!!! Always Stuck <#12afb697e122ca05_group_thread_4>[2 > Updates] > > Topic: Explain<http://groups.google.com/group/algogeeks/t/11fdf6ccb127e26e> > > saurabh agrawal <saurabh...@gmail.com> Sep 09 07:22PM +0530 > ^<#12afb697e122ca05_digest_top> > > Can somebody explain how the macros are expanded regarding order in > which > they are used...etc... > > also explain this example : > > #define A B > #define B A > > what is the effect of this and whether it will go in an infinite > recursive > call or not and why? > > > > > umesh kewat <umesh1...@gmail.com> Sep 09 10:33PM +0530 > ^<#12afb697e122ca05_digest_top> > > Hi saurabh, > > it will not going to infinite... > > 1st all A will be replaced by B so later #define B B be remaining so > this statement is valid.. program will going to execute fine.. > > > -- > Thanks & Regards > > Umesh kewat > > > > > saurabh agrawal <saurabh...@gmail.com> Sep 10 09:59AM +0530 > ^<#12afb697e122ca05_digest_top> > > @umesh kewat > > #include<stdio.h> > int main(){ > int A =4; > #define A B > #define B A > printf("%d",A); > return 0; > } > > This code works fine...but as you have explained the later A used in > printf > statement must have replaced by B. In that case there must be a > compiler > error "The identifier not defined". But this code compiless fine. and > there > seems no visible effect of these two macros. > > > > > Ayush Mittal <ayushmittal2...@gmail.com> Sep 10 02:39PM +0530 > ^<#12afb697e122ca05_digest_top> > > this code is working fine,whether u have defined B or not and if you > replace > A with B in two macros it is still running well giving output 4 in each > case > > > > > > praveen <praveen200...@gmail.com> Sep 10 02:58AM -0700 > ^<#12afb697e122ca05_digest_top> > > After preprocessing > > Where ever there is 'A' in your program, it is replaced by 'B' > Where ever there is 'B' in your program, it is replaced by 'B' > > this will be the program look like > #include<stdio.h> > int main(){ > int B =4; > > printf("%d",B); > return 0; > > } > therefore, the program will compile and run :) > > > > > umesh kewat <umesh1...@gmail.com> Sep 10 02:35PM +0530 > ^<#12afb697e122ca05_digest_top> > > HI Saurabh, > > #include<stdio.h> > int main() > { > int A =4; > > #define A B > #define B A*3 > printf("%d",A); > return 0; > } > > Above example will explain ur doubt... > > > -- > Thanks & Regards > > Umesh kewat > > > > > umesh kewat <umesh1...@gmail.com> Sep 10 03:51PM +0530 > ^<#12afb697e122ca05_digest_top> > > HI, > > Here are some fact related to macros.. > > its a preprocessor directory so before comping the code will replaced > by > appropriate macros... these are not comping or executing ..so macros > replaced one by one and other fact macro will not replaced the content > of > other macros... > > so code of 1st code will be like that after preprocessing > > 1st all A will be replaced by B except #define B A, > 2nd replaced in code where ever is B is replaced by A so like.. > > sorry for my 1st post giving wrong explanation... > > > @saurabh in ur 2nd post > > after preprocessing of 1st macro code be like that > > include<stdio.h> > int main(){ > int A =4; > #define B A > > printf("%d",B); > return 0; > > } > > after 2nd preprocessing > > include<stdio.h> > int main(){ > int A =4; > > printf("%d",A); > return 0; > > } > so out put is 4 > > if need more explanation of above logic you can see by running those > example > > #include<stdio.h> > int main() > { > int A =4; > > #define A B > #define B A*3 > printf("%d",A); > return 0; > } > > #include<stdio.h> > int main() > { > int A =4; > > #define A B*B > #define B A > printf("%d",A); > return 0; > } > > > the 1st statement will not affect by preprocessor becoz those macros > definition are coming after that otherwise u can see > > #include<stdio.h> > int main() > { > int A =4; > > printf("%d",B) > #define A B > > return 0; > } > > > > for some more > > #include<stdio.h> > int main() > { > int A =4; > > printf("%d",A); > > printf("%d",B); > > #define A B > > printf("%d",B); > #define B A > > printf("%d",B); > printf("%d",A); > > return 0; > } > > by looking compilation error u will able to see the scope of macros > and their preprocessing .. > > > > thanks for reading long post.. :) > > > > -- > Thanks & Regards > > Umesh kewat > > > > > saurabh agrawal <saurabh...@gmail.com> Sep 10 04:25PM +0530 > ^<#12afb697e122ca05_digest_top> > > Thanks a lot umesh...but still i am in confusion that: > > after first processing : "A is replaced by B" > after second proecessing " B is replaced by A" > then why again this A is not being replaced by #define A macro.. > why it is not going in an infinite loop...because i think there is no > fiexed > order of execution of the macro.. > even if you change the order in which macros are defined will make no > effect... > > > > Topic: I want improve my > algorithm??<http://groups.google.com/group/algogeeks/t/92f857877507c4f8> > > ashwin <ashwin4e...@gmail.com> Sep 09 05:22AM -0700 > ^<#12afb697e122ca05_digest_top> > > hi i am too the same.. The only way to improve is to practice solving > more and more problems. Try solving simple programming problems and > progress from there.. Good Luck > > > > > > soundar <soundha...@gmail.com> Sep 09 11:59PM -0700 > ^<#12afb697e122ca05_digest_top> > > www.spoj.pl > www.topcoder.com/tc > www.codechef.com > > > Solve problems from these sites...... > > > > Topic: how we can access 2nd element of an > struct<http://groups.google.com/group/algogeeks/t/339a1f7d69ad15ce> > > soundar <soundha...@gmail.com> Sep 09 10:46AM -0700 > ^<#12afb697e122ca05_digest_top> > > It is giving me error........."invalid cast from type ‘main()::node’ > to type ‘char*" > > > > > soundar <soundha...@gmail.com> Sep 09 10:47AM -0700 > ^<#12afb697e122ca05_digest_top> > > can you explain?thanks in advance > > > > > Sathaiah Dontula <don.sat...@gmail.com> Sep 09 01:20PM +0530 > ^<#12afb697e122ca05_digest_top> > > I think the question should have been quite generic, if it is integer > you > can go from the void pointer to four bytes ( sizeof(int)) ahead and get > the > next number that is what is required for us. But what if we do not know > what > is the member type is ?, How we can get the second member if the first > member type of the structure is not know. > > a=(float *)((char *)a+sizeof(node)-sizeof(int)); ==> Just modified to > subramani. > > Thanks, > Sathaiah Dontula > > > > > Topic: > Graphs...<http://groups.google.com/group/algogeeks/t/7df7b32307edc9d3> > > Gene <gene.ress...@gmail.com> Sep 09 01:33PM -0700 > ^<#12afb697e122ca05_digest_top> > > A DAG naturally has sources - vertices with only out-going edges - and > sinks - vertices with only incoming edges. All edges with a maximal > number of edges run from a source to a sink (why?). You can find them > most easily with a breadth-first search starting simultanously from > all the sources. > > > > > Topic: Recursion!!!!!!!!!!! Always > Stuck<http://groups.google.com/group/algogeeks/t/8000787e16954967> > > bittu <shashank7andr...@gmail.com> Sep 09 12:02PM -0700 > ^<#12afb697e122ca05_digest_top> > > Can Anyone explain me how recursion works in C. > i will be thankfull if he/she will use an example of > towerofhanoi .??????????????? > > Regards > Shashank > > > > > albert theboss <alberttheb...@gmail.com> Sep 10 01:11AM +0530 > ^<#12afb697e122ca05_digest_top> > > Its easy only .... > > tower of hanoi consist of three pegs peg A,peg B,peg C. > which is used as BEG,AUX,END > > Let n be 5 for example... > > wat u r going to do is > > step 1 : move the top n-1 (4) disks from BEG to AUX... > in this case END will be used as auxiliary. > > step 2: move the n th disk from BEG to END . > use AUX as auxiliary in this case > > step 3: move the n-1(4) disks from AUX to END that is moved in step 1 > use BEG as auxiliary in this step > > > Actual code is > > void tower(int n,char beg,char aux,char end) > { > if(n>0) > { > tower(n-1,beg,end,aux); // move n-1 disks from beg to > aux > printf("%c->%c",beg,aux,end);//equivalent to > tower(1,beg,aux,end) move 1 disk from beg to end > tower(n-1,aux,beg,end) // move disks from aux to end > } > } > > again that n-1 disks are moved to end which is called recursively..... > > Still u have doubt??? > > > > -- > You received this message because you are subscribed to the Google Groups > "Algorithm Geeks" group. > To post to this group, send email to algoge...@googlegroups.com. > To unsubscribe from this group, send email to > algogeeks+unsubscr...@googlegroups.com<algogeeks%2bunsubscr...@googlegroups.com> > . > For more options, visit this group at > http://groups.google.com/group/algogeeks?hl=en. > -- You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. 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