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11. Integer number of values

1#include <iostream>2 3 intError =0;4 DoublePower (Double Base,intexponent);5 6 intMainintargcChar*argv[]) {7   Double Base;8   intexponent;9Std::cin >>Base>>exponent;Ten   One   Doubleresult = Power (Base, exponent); A    -Std::cout << Error <<Std::endl; -Std::cout << Result <<Std::endl; the } -  - DoublePower (Double Base,intexponent) { -   if(0==exponent) +     return 0; -   if(Exponent >0) {//the index is positive +     if(1==exponent) A       return Base; at     if(Exponent%2==0) {//even -       DoubleTMP = Power (Base, exponent/2); -       returntmp*tmp; -}Else{//Odd -       DoubleTMP = Power (Base, (exponent-1)/2); -       returntmp*tmp*Base; in     } -}Else{//index is negative to     if(Base==0) { +Error =-1; -       return 0; the     } *     if(-1==exponent) $       return 1/Base;Panax Notoginseng     if(Exponent%2==0) {//even -       DoubleTMP = Power (Base, exponent/2); the       returntmp*tmp; +}Else{//Odd A       DoubleTMP = Power (Base, (exponent+1)/2); the       returntmp*tmp* (1/Base); +     } -   } $}

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*book:

1#include <iostream>2 3 BOOLError =false;4 DoublePower (Double Base,intexponent);5 DoublePositivepower (Double Base, unsignedintexponent);6 BOOLEqualDoubleMDoublen);7 8 intMainintargcChar*argv[]) {9   Double Base;Ten   intexponent; OneStd::cin >>Base>>exponent; A   -   Doubleresult = Power (Base, exponent); -    theStd::cout << Error <<Std::endl; -Std::cout << Result <<Std::endl; - } -  + DoublePower (Double Base,intexponent) { -   //Base is 0, exponent is negative/0/positive +   if(Equal (Base,0.0)) { A     if(Exponent <0) { atError =true; -       return 0; -}Else -       return 0; -   } -  in   //exponent is positive/0 -UnsignedintAbsexponent = (unsignedint) exponent; to   if(Exponent <0) { +Absexponent = (unsignedint)(-exponent); -   }  the   Doubleresult = Positivepower (Base, absexponent); *   return(Exponent <0) ?1/Result:result; $ }Panax Notoginseng  - BOOLEqualDoubleMDoubleN) { the   if(M-n <0.0000001&& m-n >-0.0000001) +     return true; A   return false; the } +  - DoublePositivepower (Double Base, unsignedintexponent) { $   if(Exponent = =1)  $     return Base; -   if(Exponent = =0) -     return 0; the   Doubleresult = Positivepower (Base, exponent >>1); -Result *=result;Wuyi   if(Exponent &0x1==1)//Odd theResult *=Base; -   returnresult; Wu}

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Idea: The nature of using the exponentiation

The subject seems simple, but the perfect writing procedure needs to be considered comprehensively:

1) The base/exponent is 0, negative, positive; (A's N power is the reciprocal of A's-N power, which can be used to simplify the program.)

2) The method of base judgment is 0 (double base== 0 error);

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