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Re: rand() function and array 14 Years Ago by Ancient Dragon rand() returns integers, not doubles or floats, so you might as well declare setNum as an array of integers. And the code you posted does not even reference that array nor does it ever call rand() rand() Help 14 Years Ago by God Coder123 If i had an Array as seen below, is it possible to use the rand function to randomly select an element within that particular array; if so how can this be done. The Value of the element will be outputted. Any help much appreciated...:) [CODE]int Array[14]={10,10,10,10,11,6,9,2,3,15,11,15,16,15};[/CODE] Re: rand() Help 14 Years Ago by daviddoria Does this help? [code] int RandomInt(const int MAX) { //produce an int from 0 to MAX-1 return rand() % MAX; } [/code] Dave Re: rand() Help 14 Years Ago by Aranarth [code]const int arraySize=sizeof(Array)/sizeof(*Array); cout << Array[rand()%arraySize] << endl;[/code] Re: rand() Help 14 Years Ago by Sandhya212 … namespace std; void seed(){ srand(time(0)); } double Randunif(){ return rand() / double(RAND_MAX); } double Randunif(double x){ return ((Randunif()*x)+1… Re: rand() Help 14 Years Ago by God Coder123 Thanks Guys. This method works great, thanks Aranarth. Here's what i got: [CODE]srand ( time(NULL) ); int Array[]={1,2,6,7,8,89}; const int arraySize=sizeof(Array)/sizeof(*Array); cout << Array[rand()%arraySize] << endl;[/CODE] Although i don't really understand the method, Perhaps you could enlighten me Aranarth. Re: rand() Help 14 Years Ago by God Coder123 Sweet, i see what you mean Dave This is what ive got: [CODE]vector<int>array; array.push_back(1); array.push_back(2); array.push_back(6); const int arraySize=array.size(); cout << array[rand()%arraySize] << endl;[/CODE] BTW what does the .size(); function actually do here. :) rand() 11 Years Ago by nitin1 can you please tell me how rand () is implemented ? i know it is library implementaion dependent. but … Re: rand() 11 Years Ago by Moschops … been done, in glibc Version 2.15; the call to rand ends up at the function __random_r in this implementation http… Re: rand() 11 Years Ago by deceptikon > but still can you tell me the way in which it is mostly implemented ? rand() is usually implemented with some form of [linear congruential generator](http://eternallyconfuzzled.com/tuts/algorithms/jsw_tut_rand.aspx). Rand Max Problem 18 Years Ago by punter …; countoccurence(1); } ] int generatehighvalue (int valuetrials) [ int num, compare; num = rand(); compare = 0; if (trials > 1) compare = generatehighvalue(trials - 1… 3260 8 3295 9 3330 missing 0 of 10 Testing rand()%n for n = 16 0 2073 1 1983 2 2030… Rand in a 2D array, duplicating locations! 14 Years Ago by Leppie …; p<100 ; p++ ) { randx =rand()% 10; randy =rand()% 10; array_check[randx][randy]=1; if (p ==…p << endl; //do { // randx =rand()% 10; // randy =rand()% 10; // if (array_check[randx][randy]!=2) // …=0; n<=98; n++) // { // randx =rand()% 10; // randy =rand()% 10; // array_check[randx][randy]=1; // } //for … Re: Rand in a 2D array, duplicating locations! 14 Years Ago by NathanOliver …zeroY; int map[10][10]; srand((unsigned)time(0)); zeroX = rand() % 10; // this gets the spot to put the zero …zeroY = rand() % 10; // place zero map[zeroX][zeroY] = 0; while (counter &…lt; 100) { x = rand() % 10; y = rand() % 10; if (x == zeroX && y == zeroY) //… Re: Rand in a 2D array, duplicating locations! 14 Years Ago by Leppie …but it didn't solve the problem as rand still overwrites itself in your code as well.…each element with a 0. I then use rand to randomly select an element and change that…are never 10 lots of 1. (Duplicity of rand overwrites already placed 1's, leaving me less… therefore need to check the value of where rand will place the number 1 before its actual … Re: Rand in a 2D array, duplicating locations! 14 Years Ago by VernonDozier …; 10) // check whether we have ten ones yet { int index = rand () % 20; // pick a random index if (array[index] != 1) // check… Rand function not working very well. 15 Years Ago by rkulp …; srand(unsigned(time(NULL))); Temp1 = Dice[(rand()%16)]; Temp2 = Dice[(rand()%16)]; while (Temp1 == Temp2) { Temp2 = Dice[(rand()%16)]; } Dice[Temp1] = Temp2; Dice… Re: Rand function not working very well. 15 Years Ago by justice igwe …; srand(unsigned(time(NULL))); Temp1 = Dice[(rand()%16)]; Temp2 = Dice[(rand()%16)]; while (Temp1 == Temp2) { Temp2 = Dice[(rand()%16)]; } Dice[Temp1] = Temp2; Dice…[Temp2] = Temp1; Side[Temp1] = (rand()%6); Side[Temp2] = (rand()%6); }[/CODE][/QUOTE] Note check the srand(unsigned(time… Rand Number isn't Random! 15 Years Ago by Jerail …;10;i++) // loop thru 10 times... { numbers[i] = (rand()%100); // get a rand num cout << numbers[i] << endl… to screen (+ linebreak) sum = sum + numbers[i]; // add rand num to total sum if(numbers[i]>=0 &&… Re: Rand function not working very well. 15 Years Ago by dusktreader You have some value index confusion happening here I think Try [code=c++] int temp; int idx0 = rand() % 16; int idx1 = idx0; while( idx1 == idx0 ) idx1 = rand() %16; temp = Dice[idx0]; Dice[idx0] = Dice[idx1]; Dice[idx1] = temp; [/code] Re: Rand Array Help please, my code isn't working 11 Years Ago by Labdabeta … algorithm has a fatal flaw. You should realize that rand() is random (or at least relatively close to random… would happen to your code if, for example, rand() always returned 4 (http://xkcd.com/221/) of course…<array_size; ++i) { //swap(array[rand()%i],array[i]); int rnd=rand()%i; int tmp=array[rnd]; array[rnd]=array… Re: Rand function not working very well. 15 Years Ago by Salem > (I loop it 250 times) ... > srand(unsigned(time(NULL))); Unless your code also takes 250 seconds to run, then srand() is always going to be seeded with the SAME value, and rand() is always going to return the SAME value(s) as a result. srand() needs to be called ONCE only, at the start of main. Re: Rand function not working very well. 15 Years Ago by mrnutty … always going to be seeded with the SAME value, and rand() is always going to return the SAME value(s) as… Re: Rand function not working very well. 15 Years Ago by hag++ … always going to be seeded with the SAME value, and rand() is always going to return the SAME value(s) as… rand() function without < stdlib.h> header 12 Years Ago by ashish2expert … have not defined <stdlib.h> header and included rand() function and it works without this header. How? #include <…("Your hand: "); while(num_cards > 0) { suit = rand() % NUM_SUITS; rank = rand() % NUM_RANKS; if(!in_hand[suit][rank]) { in_hand[suit][rank] = true… Re: Rand Array Help please, my code isn't working 11 Years Ago by vijayan121 … ) ; std::srand( std::time(nullptr) ) ; std::seed_seq seed_seq { std::rand(), std::rand(), std::rand(), std::rand() } ; std::shuffle( begin, end, std::mt19937(seed_seq) ) ; for… rand and srand 10 Years Ago by lewashby In the program below what is the difference between rand and srand? My book says that rand returns an int between 0 and RAND_MAX, which is never smaller than 32,767. Yet this code returns a number from 1-6, how is that? I see the line `( rand() % 6 ) + 1` but I don't see how that would give a number from 1-6. Re: rand and srand 10 Years Ago by deceptikon > In the program below what is the difference between rand and srand? `rand` generates a pseudorandom number. `srand` seeds the generator that… `rand` uses. The seed essentially determines what the first random number … Re: rand() range help 17 Years Ago by joshua.tilson > `int high=10;` > `int low=6;` > `rand () % (high - low + 1) + low;` Hello, I was hoping some one could shed some light on the reason this works. I have used rand() in the past to simulate rolling dice (1-100 etc.). I have never used the minimum number like this. why is it that `rand() % 11` = a range of 6 - 10? Thank you! Re: Rand Number isn't Random! 15 Years Ago by jonsca [icode]#include <ctime>[/icode] and call [icode] srand((unsigned)time(0)); [/icode] (once) before you call rand(). Re: rand() function and array 14 Years Ago by Ancient Dragon … loop? The while loop should do nothing more than call rand() for each element of the array. There is no point… to change all the elements to the value returned by rand(). >>line 27 I belive I called…