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Showing posts from September, 2011

Difference between foo(void) and foo()

Source:http://stackoverflow.com/

Problem:
Consider these two function definitions
void foo(){ ... }void foo(void){ ..... } What is the difference between these two functions?

Hint: The answer depends whether this is C code or C++ code.

C code 32 bit vs 64 bit

Source: http://www.gowrikumar.com

Problem:
The following C program segfaults of IA-64, but works fine on IA-32.

intmain() { int*p; p= (int*)malloc(sizeof(int)); *p=10; return0; }Update (Oct 30, 2011):
Wrong problem. Sorry for the trouble.

C++ Macro Concatenation

Source:http://www.gowrikumar.com
Problem: What is the output of the following C++ code?
#include<stdio.h>#definef(a,b) a##b#defineg(a) #a#defineh(a) g(a)intmain() { printf("%s\n",h(f(1,2))); printf("%s\n",g(f(1,2))); return0; }Update (14 Sept 2011):
Solution posted in comments by Prathmesh Prabhu (CSE IITB 2010 Alumnus and Wisonsin Madison II-year Graduate Student)

Arrange in a Sequence

Source:
Asked to me by Amol Sahasrabudhe (IITB 2004 Alumnus, Worked at Morgan Stanley Quant Division, Deutsche Bank)

Problem:
You are given 2n numbers ( 1 to n and 1 to n ). You have to arrange these numbers in a sequence such that between any two i`s, there exists exactly i-1 numbers. Is it possible for all n? If no, what are the values of n for which this is possible?

Disclaimer:
I have not been able to solve it. Sudhanshu Tungare (IITB 2008 EE Alumnus, Morgan Stanley) claims to have a solution. Cheers!

Update (November 1, 2011):
Part solution posted by Nishant Totla (CSE IITB Senior Undergraduate), Richie and Sarat in comments! Complete solution posted by Siddhant Agarwal (EE IITB Alumnus, CMI Grad student) in comments! Thanks a ton.