function_rand

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1、functionrandintrand(void);GeneraterandomnumberReturnsapseudo-randomintegralnumberintherange0toRAND_MAX.Thisnumberisgeneratedbyanalgorithmthatreturnsasequenceofapparentlynon-relatednumberseachtimeitiscalled.Thisalgorithmusesaseedtogeneratetheseries,whichshouldbeinitializedtosom

2、edistinctivevalueusingsrand.RAND_MAXisaconstantdefinedin.Itsdefaultvaluemayvarybetweenimplementationsbutitisgrantedtobeatleast32767.Atypicalwaytogeneratepseudo-randomnumbersinadeterminedrangeusingrandistousethemoduloofthereturnedvaluebytherangespanandaddtheinitialvalueoftheran

3、ge:(value%100)isintherange0to99(value%100+1)isintherange1to100(value%30+1985)isintherange1985to2014Noticethoughthatthismodulooperationdoesnotgenerateatrulyuniformlydistributedrandomnumberinthespan(sinceinmostcaseslowernumbersareslightlymorelikely),butitisgenerallyagoodapproximationfors

4、hortspans.Parameters(none)ReturnValueAnintegervaluebetween0andRAND_MAX.Example1234/*randexample:guessthenumber*/#include#include#includeintmain(){56789101112131415161718intiSecret,iGuess;/*initializerandomseed:*/srand(time(NULL));/*generatesecretnumber:*/iSec

5、ret=rand()%10+1;do{printf("Guessthenumber(1to10):");scanf("%d",&iGuess);if(iSecretiGuess)puts("Thesecretnumberishigher");}while(iSecret!=iGuess);puts("Congratulations!");return0;}Output:Guessthenumber(1to10):5Thesecretnumberishigher

6、Guessthenumber(1to10):8ThesecretnumberislowerGuessthenumber(1to10):7Congratulations!Inthisexample,therandomseedisinitializedtoavaluerepresentingthesecondinwhichtheprogramisexecuted(timeisdefinedintheheader).Thiswaytoinitializetheseedisgenerallyagoodenoughoptionformostrandomingne

7、eds.