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# Perfect Squares

 P: n/a Q-1 Can sm1 suggest a program to check whether a given no is perfect square or not?? Q-2 Also sm1 suggest a program to check whether a given no is perfect power or not?? * PEfect power is a no which can be expressed some power of a any noo. Its better if it is very efficient! Jun 16 '07 #1
4 Replies

 P: n/a Also (and obviously) use of lib-funcs like pow() and sqrt() is not allowed Jun 16 '07 #2

 P: n/a "The 1"

 P: n/a The 1 said: Q-1 Can sm1 suggest a program to check whether a given no is perfect square or not?? I'm not sure what you mean by "sm1" or "no" (in the context). I'm guessing at "someone" and "number", but I'm not certain that my guesses are correct. The important thing about homework is to try doing it for yourself. That's a vital part of the learning process. To start you off: The term "perfect square" suggests that this is an exercise in integers. The highest value one can portably represent in a native unsigned integer type is 4294967295, which is just a shade short of being a perfect square itself. To be able to represent this, use unsigned long int. The highest perfect square that can be portably represented in an unsigned long int is 4294836225. The lowest perfect square you can represent in an unsigned long int is 0 (or, if you don't count that, 1). So you have lower and upper bounds on your problem. Your next step is to capture a value from the user, and ensure it is within the range 0 (or 1) to 4294836225. If it isn't, it might yet be a perfect square, but not one that you can handle easily within the context of a simple homework exercise, so you can reject it as being outside the supported range. Now you need to find the integer that is closest to the square root of the number. You can find this via binary search. Now multiply that number by itself. If it is equal to the input number, the answer is "yes, this is a perfect square". Otherwise, the answer is "no, this is not a perfect square". Q-2 Also sm1 suggest a program to check whether a given no is perfect power or not?? I suggest you finish Question 1 before attempting Question 2. -- Richard Heathfield "Usenet is a strange place" - dmr 29/7/1999 http://www.cpax.org.uk email: rjh at the above domain, - www. Jun 16 '07 #4

 P: n/a "The 1" #include #include struct Power { int Is; long Base, Expon; } is_power(long n) { struct Power result; result.Is = 1; result.Base = n; result.Expon = 1; return result; } int main(int argc, char *argv[]) { long n; char *end; struct Power is; if (argc < 2) { fputs("Provide a number, please...\n", stderr); exit(EXIT_FAILURE); } n = strtol(argv[1], &end, 10); if (*end != '\0') printf("Whatever garbage you mean by \"%s\" will be " "ignored.\n", end); if (errno == ERANGE) printf("The number you wrote is too large or too small, " "let's pretend you wrote %ld.\n", n); is = is_power(n); if (is.Is) printf("%ld is a perfect power as it equals %ld**%ld.\n" n, is.Base, is.Expon); else printf("%ld is not a perfect power."); return 0; } Jun 17 '07 #5

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