# Category: Mathematics

• ## Project Euler Problem 2, solution internals related using ruby debugger

\$ruby -rdebug euler-two.rb Debug.rb Emacs support available. /usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:57: RUBYGEMS_ACTIVATION_MONITOR.enter (rdb:1) r /usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:57: RUBYGEMS_ACTIVATION_MONITOR.enter (rdb:1) r /usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:57: RUBYGEMS_ACTIVATION_MONITOR.enter (rdb:1) next /usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:143: RUBYGEMS_ACTIVATION_MONITOR.exit (rdb:1) next euler-two.rb:3:n1, n2 = 1, 2 (rdb:1) next euler-two.rb:4:sum = 0 (rdb:1) print n1 1nil (rdb:1) print n2 2nil (rdb:1) next euler-two.rb:6:while n2 < 4000000 (rdb:1) print n2 2nil (rdb:1) next euler-two.rb:7:sum +=…

• ## Project Euler Problem 3, solution internals using python debugger

\$python -m pdb euler-three.py > /home/jeffrin/beautifulwork/lib/euler-three.py(7)() -> ”’ (Pdb) r 6857 –Return– > /home/jeffrin/beautifulwork/lib/euler-three.py(17)()->None -> print n (Pdb) next –Return– > (1)()->None (Pdb) next The program finished and will be restarted > /home/jeffrin/beautifulwork/lib/euler-three.py(7)() -> ”’ (Pdb) next > /home/jeffrin/beautifulwork/lib/euler-three.py(9)() -> n = 600851475143 (Pdb) next > /home/jeffrin/beautifulwork/lib/euler-three.py(11)() -> i = 2 (Pdb) next > /home/jeffrin/beautifulwork/lib/euler-three.py(12)()…

• ## How to write an algorithm to find among natural numbers the sum of multiples of 3 and 5 below 1000 ?

/* This program has been worked on from http://www.s-anand.net/euler.html */ #include <stdio.h> sofmul() { int n, i; n = 0; for (i = 0 ; i < 1000 ; i++) { if ( !(i % 5) || !(i % 3) ) n = n + i; } printf(“Sum of the multiples of 3 and 5…

• ## How to write a program to multiply a number by 4 using a bitwise operator ?

/* Part of this program copied from http://www.sanfoundry.com/c-program-multiply-number-4-using-bitwise-operators/ */ #include <stdio.h> multbitwise() { long number; printf(“Enter an integer: “); scanf(“%ld”,&number); number = number << 2; printf(“Result is %ld \n”,number); } /* http://stackoverflow.com/questions/4456442/interview-multiplication-of-2-integers-using-bitwise-operators */ /* http://www.geeksforgeeks.org/multiply-two-numbers-without-using-multiply-division-bitwise-operators-and-no-loops/ */ /* http://en.wikipedia.org/wiki/Bitwise_operation */

• ## How to write an algorithm to do a binary to decimal conversion ?

/* part of work copied from http://www.sanfoundry.com/c-program-binary-number-into-decimal/ */ #include <stdio.h> btd() { int num, binary_val, decimal_val = 0, base = 1, rem; printf(“Enter a binary number : “); scanf(“%d”,&num); binary_val = num; while ( num > 0 ) { rem = num % 10; decimal_val = decimal_val + rem * base; num = num /…

• ## Hacking with integer divisibility

/* work copied from http://www.sanfoundry.com/c-program-number-divisible-by-5/ */ #include <stdio.h> numberdivi() { int i, num1, num2, count = 0, sum = 0; printf(“Enter the value of num1 and num2 : “); scanf(“%d %d”,&num1,&num2); for (i = num1; i < num2 ; i++) { if ((i % 5) == 0) { printf(“%3d,”,i); count++; sum = sum + i;…

• ## How to write an algorithm to find factorial of a given number ?

#include <stdio.h> factorial() { int p = 1; int i = 1; int n; printf(“Enter a Number greater than 0 \n”); scanf(“%d”,&n); while ( i <= n) { p = p * i; i = i + 1; } printf(“Factorial of the input is %d \n”,p); }

• ## Hacking with an algorithm to find prime factor of a number

\$./app Sign detection  Power of two  Counting No. of bits set  Set or clear bits without branching Find maximum value Finding least common multiple Finding the greatest commom divisor Finding if a number is an Armstrong number or not Finding if a given number is prime number Finding the number of twin…

• ## Tinkering with an Armstrong number finding program function

\$./app Sign detection  Power of two  Counting No. of bits set  Set or clear bits without branching Find maximum value Finding least common multiple Finding the greatest commom divisor Finding if a number is an Armstrong number or not 8 Enter a positive integer: 153 153 is an Armstrong number \$./app Sign…