JavaScript Random Number Generator

4 New Member

I like to make a javascript that generate random number from the range number within : (10016486 and 99999985).
the number always + 22423 that begin from 10016486 and end at 99999985
Example random result from generate button :

10016486 + 22423 = 10038909
10038909 + 22423 = 10061332 and so on, maximum to 99999985

or if somebody can convert below c++ code to working javascript/html random number generator.

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 #include <cstdlib> 

#include <ctime> 

#include <iostream>
 
using std::cout;
 
int main( ) {
 
  // srand will set a random starting point for rand()

  // We use the time as a seed, as it's always changing

  srand( ( unsigned )time( 0 ) ); 
 
  // We generate a random number between 0 and 4013

  // 4013 because ( 22423 * 4013 => 89983499 and

  // 89983499 + 10016486 => 99999985 - our max value )

  int randomKey = rand() % 4013; 
 
  // Output the generated key and don't immediately close the command prompt window

  cout << "Your random key is: " << ( 10016486 + ( randomKey * 22423 ) ) << "\n"; 

  system( "PAUSE" );
 
  return 0;

}

Thanks for any help.

Jul 16 '06 #1

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16722

iam_clint

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Recognized Expert Top Contributor

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<html>

<body>

<script>

function randomnumber() {

    document.getElementById("rand").value = Math.round((99977562 - 10016486) * Math.random() + 1) + 22423;

//alright so 99977562 because 99977562 + 22423 = 99999985 and thats the max don't want to go over.

//so what i did here was first 99977562 - 10016486 x math.random() + 1 + 22423

}

</script>

<input type="text" name="rand" id="rand">

<input type="button" value="insert" onclick="randomnumber();">

</body>

</html>

thats what i came up with by your explanation but that doesn't look like whats the c code is doing good luck

Jul 16 '06 #2

L33VaNcL33F

New Member

Thanks for the script.

But the generated value is not valid.
I don't know where is the wrong.

Jul 17 '06 #3

iam_clint

1,208

Recognized Expert Top Contributor

Try to explain your question alittle more

i'll try to convert the C+ code

Jul 17 '06 #4

iam_clint

1,208

Recognized Expert Top Contributor

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<script>

function randomnumber() {

    //alrighty this is basicly doing the same as rand() % 4013 all that says is a random number between 0 and 4013

    randomkey = Math.floor(Math.random()*4013);

    //next step is do add 10016486 + (the random number * 22423) for the final value

    document.getElementById("rand").value = (10016486 + (randomkey * 22423));

}

</script>

<input type="text" name="rand" id="rand">

<input type="button" value="Get Random Key" onclick="randomnumber();">

</body>

</html>

this is what i came up with i tried to do exactly what the C program is doing.

i think this is more along the lines of what you are looking for. let me know if everything works out

Jul 17 '06 #5

Banfa

9,065

Recognized Expert Moderator Expert

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//alrighty this is basicly doing the same as rand() % 4013 all that says is a random number between 0 and 4013

randomkey = Math.floor(Math.random()*4013);

Actually

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rand() % 4013

produces a number between 0 and 4012 because 4013 % 4013 = 0. On a C/C++ note this is a really bad way to produce a small random number because the normal pseudo random number generator used in most (well a lot) of C implementations doesn't have very good randomness in the lower order bits of the value

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(rand()/(MAX_RAND/4013))%4013

is better although you have a slightly greater chance of getting 0 than any other number. This can be eliminated but it takes more lines of code than I care to type here since it is in an irrelevent language.

Jul 17 '06 #6

iam_clint

1,208

Recognized Expert Top Contributor

Thanks for the explanations i don't do much c coding but my javascript code should be producing the same results? Is it correct or did i miss something that c is doing that the javascript i made for him isn't doing? the first one i made was off his explination the second one was based off the c++ code if you have a javascript solution to his answer please post it i did what i could as to converting the C++ code.

I think it should generate the numbers in the correct range that he wanted.

Jul 17 '06 #7

L33VaNcL33F

New Member

Thanks for the explanations i don't do much c coding but my javascript code should be producing the same results? Is it correct or did i miss something that c is doing that the javascript i made for him isn't doing? the first one i made was off his explination the second one was based off the c++ code if you have a javascript solution to his answer please post it i did what i could as to converting the C++ code.

I think it should generate the numbers in the correct range that he wanted.

Oh really thank you iam_clint,
The second one generated the right value.

My first C++ code is too simple. but below is some additional code.
Need some help again how to add prefix like ABC in front of the generated value number, for example ABC12345678. Thanks for the script.

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 #include <iostream> 

#include <ctime> 

#include <cstdlib>
 
using namespace std;
 
int main() 

{ 

    srand((unsigned)time(0));

    int random_integer = rand() % 4013;

    int lowest=0, highest=4013; 

    int range=(highest-lowest)+1; 

    for(int index=0; index<20; index++){

        random_integer = lowest+int(range*rand()/(RAND_MAX + 1.0)); 

        cout << "Your random numbers is: ABC" << ( 10016486 + ( random_integer * 22423 ) ) << "\n"; 

        system( "PAUSE" );

    } 

}

Jul 20 '06 #8

iam_clint

1,208

Recognized Expert Top Contributor

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<script>

function randomnumber() {

    randomkey = Math.floor(Math.random()*4013);

    document.getElementById("rand").value = "abc" + (10016486 + (randomkey * 22423));

}

</script>

<input type="text" name="rand" id="rand">

<input type="button" value="Get Random Key" onclick="randomnumber();">

</body>

</html>

this would produce abc then the random number i did not change any of the javascript code to match up with your new C++ code. just added the string

Jul 20 '06 #9

L33VaNcL33F

New Member

Thank You very much iam_clint,
You give me an inspiration about coding.
I will study JavaScript code deeply and seriously.

With this help, I got many knowledge and clues how to coding.
Thanks again.

Jul 21 '06 #10

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