Some interesting observations in C++

//I used Dev C++ Ver 5.11 (compiler) ... i told since some of this might run differently on other IDEs

Some interesting observations in C++
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1. About pow() function
*pow() cant find 'fractional' powers, but can find decimal powers
for eg. pow(4,1/2) gives 1;
but, pow(4,0.5) gives 2;
     pow(4,0.55) gives 2.14;

*roots of negative numbers:
pow(-4,0.5) gives "nan"

2. Time Battle between cout and for loop (UnExpEcTEd)
In this program, see the time taken by them (individually) "on my computer" (on faster computers there may be more/less gap)

#include<iostream>
using namespace std;
int main()
{

//for(int i=1; i<100000;i++);  //0.215 sec
cout<<"hello";  //0.303 sec
}

3. Dont ask user to enter 0, if you are going to use an IF statement, because 0 is treated as false; instead ask for -1 instead of 0 (*you may even as for any other number)
For eg. cout<<"Enter 0 if you want to exit : "; cin>>choice;
if(choice==0) exit;
else goto proceed;

//in this piece of code, even if the user enters 0, the if will become false, and hence will not exit
//ALTERNATIVE (Not recommended) - you may go like this : "if(choice!=0) exit;" but if the user is asked to enter number choice from a menu, for eg. then the program will exit instead of proceeding :p

4. About the size of array...
   When you declare an array globally, you will have to give its size also
   When you declare an array in a function, you will have to give its size also
   When you declare an array in a CLASS or STRUCT, you are NOT REQUIRED TO GIVE ITS SIZE
   When you declare an array in a FUNCTION'S PROTOTYPE, you are NOT REQUIRED TO GIVE ITS SIZE

5. C++ is CASE SENSITIVE

6. C++ printed a 100MB file in 6s (with random characters from the heap storage) on a 7 year old laptop, with an intel core i5, and 4GB DDR3 RAM

7. More to be added...