Code Forum

I'm trying to understand the differences between C and C++ with regards to void pointers. the following compiles in C but not C++ : int * p = malloc ( sizeof ( int )); However, here: void foo ( void * vptr ) { } int main () { int * p = ( int *) malloc ( sizeof ( int )); foo ( p ); return 0 ; } Both C++ and C compile it with no complain. Why?  

Determine whether a number is palindrome or not without using extra space. Don't forget to mention whether your Algo will work for negative numbers or not.

Given an array of integers, find all combination of four elements in the array whose sum is equal to a given value X. For example, if the given array is {10, 2, 3, 4, 5, 9, 7, 8} and X = 23, then your function should print “3 5 7 8″ (3 + 5 + 7 + 8 = 23). Note: Numbers should not be overlapping. eg(3,5,7,4) will generate 3+5=8 and 5+7=12 , for sum equals 20, 5 is overlapping.

Given a string containing only digits, restore it by returning all possible valid IP address combinations. For example: Given "25525511135" , return ["255.255.11.135", "255.255.111.35"] . (Order does not matter)

What is the difference in terms of program size in case of these two types of declarations int a[100]; or, int a[100]={10};

In a monetary system each coin has an integer number written on it. A coin ' n ' can be exchanged in a bank into three coins: n/2 , n/3 and n/4 . But these numbers are all rounded down. You can also sell coins for dollars and their exchange rate is 1:1. You have one gold coin. What is the maximum amount of dollars you can get for it? eg: for a coin with value 120 you can get 144 dollars. Suggest an algorithm to solve the problem.