EmbLogic » Abhilash Singh

Adding two numbers without using operators

Abhilash Singh — Tue, 11 Feb 2014 10:22:36 +0000

we have provided many utilities in printf ,in which one of it is adding two positive number (only for positive numbers).here it goes like this,

we all now that printf() On success,returns the total number of characters written. On failure, a negative number is returned.now the new thing might some of you know that ,The “%*d” format specifier causes printf() to read two integers from its arguments, the first to set the field width and the second here it is a decimal number(depends on specifier).

now using printf(“%*c%*c”,a,’ ‘,b,’ ‘); we can get the sum of the number of a and b;

but how:- the first specifier * will be width (suppose a=3 and b=2) which gives the width 3 and 2 respectively and the second is blank spaces that means the blank spaces will print on 3rd and 2nd widths and printf will return 5 is is the sum (a+b=5)

sample program

printf(“enter the 1st number\n”);
scanf(“%d”,&a);
printf(“enter the 2nd number\n”);
scanf(“%d”,&b);

printf(“%d”,printf(“%*c%*c”,a,’ ‘,b,’ ‘));
By Mukund and Abhilash

PARALLEL PORT

Abhilash Singh — Sun, 06 Oct 2013 17:01:41 +0000

compatibility mode: checked with hardware working fine now moving on Nibble mode

Multiple data compression

Abhilash Singh — Wed, 07 Aug 2013 05:10:02 +0000

completed mdc of code lenght 4 now going ahead for next code lenght.

find whether the number is power of 2 or not in one line expression

Abhilash Singh — Mon, 05 Aug 2013 06:48:09 +0000

Logic- when u convert a decimal number to its binary number then u get series of 1 and 0 ,Now if a number is power of two then u will observe it has only one (bit 1) and if you perform binary and operation of it with just a number previous to it ,then u will get Zeros.

For example

8=1000(binary form ) here u can see only one (bit 1) is there rest are zeros,
Now the number just previous to 8 is 7
so, 7=0111 and if u perform binary and operation on it as
1000(8)
(AND) 0111(7)
———
0000(0)
———
So if we perform AND operation between the number (which we want to check is a power of two or not) and the number just previous to it and result comes as zeros then its power of two otherwise it is not.

so here is the one line expression

if(!(num & (num-1))&&num)

if the above condition true then the number is of power of two otherwise it is not.