Interview Question
Senior Software Engineer Interview

MetaWrite some pseudo code to raise a number to a power.
Interview Answers
11 Answers
int raise(num, power){ if(power==0) return 1; if(power==1) return num; return(raise(num, power1)*num); }
vittal on
small mistake function power(x, n) { if n == 1 return x; // Even numbers else if (n%2 == 0) return square( power (x, n/2)); // Odd numbers else return power(x, n1) * x; }
deveffort on
double Power(int x, int y) { double ret = 1; double power = x; while (y > 0) { if (y & 1) { ret *= power; } power *= power; y >>= 1; } return ret; }
Anonymous on
# Solution for x ^ n with negative values of n as well. def square(x): return x * x def power(x, n): if x in (0, 1): return x if n == 0: return 1 if n < 0: x = 1.0 / x n = abs(n) # Even number if n % 2 == 0: return square(power(x, n/2)) # Odd number else: return x * power(x, n  1) print ("0 ^ 0 = " + str(power(0, 0))) print ("0 ^ 1 = " + str(power(0, 1))) print ("10 ^ 0 = " + str(power(10, 0))) print ("2 ^ 2 = " + str(power(2, 2))) print ("2 ^ 3 = " + str(power(2, 3))) print ("3 ^ 3 = " + str(power(3, 3))) print ("2 ^ 8 = " + str(power(2, 8))) print ("2 ^ 1 = " + str(power(2, 1))) print ("2 ^ 2 = " + str(power(2, 2))) print ("2 ^ 8 = " + str(power(2, 8)))
Abhimanyu Seth on
If I were an interviewer, I would ask the Aug 29, 2010 poster why he used bitwise operators, and whether he would deploy that code in a production environment, or if he merely wanted to demonstrate, for purposes of the interview, that he understands bitwise operations.
Ted Behling on
If the power is not integer, use ln and Taylor series
Evgeni on
If I'm the interviewer, none of above answers is acceptable. What if y < 0? what if y < 0 and x == 0? I'm seeing an endless recursion that will eventually overflow the stack, and the nonerecursive one just simply returns 1.
Jerry on
There is a way to do this in a logN way rather than N. function power(x, n) { if n == 1 return x; // Even numbers else if (n%2 == 0) return square( power (x, n/2)); // Odd numbers else return power(x, n1); } This is from Programming pearls.. interesting way.
deveffort on
Because it uses dynamic programming and is lots more efficient than your algorithm.
Dah on
In Ruby: def power(base, power) product = 1 power.times do product *= base end product end puts "2^10 = 1024 = #{power(2,10)}" puts "2^0 = 1 = #{power(2,0)}" puts "2^1 = 2 = #{power(2,1)}"
Ted Behling on
pretty trivial...
Anonymous on