Title: rand()
Description: rand()
Shonoby - January 4, 2007 01:40 AM (GMT)
Well, for a long while i have been wondering if there is a way that i can create a a rand() operation that does not start from 0 i mean like it, only choses values from a specific value like so:
a rand() operation that is only from, 50 - 100 and nothing less that 50 nor greater than 100, because with the basic 50 + rand() % 100 all it would do is add 50 to a value from 0 - 100.
So does any1 know of a keyword like this or operation or whatever?
Rmstn1580 - January 4, 2007 05:13 AM (GMT)
For your situation
| CODE |
srand(time(NULL));
int randomNumber = 50 + rand() % 100;
|
In that code, it will choose a number from 50 - 100. You can plug in any value you want in those two spots.
KTC - January 4, 2007 05:26 AM (GMT)
| CODE |
| int randomNumber = 50 + rand() % 100; |
Rmstn1580, as Shonoby already posted himself, that goes from 50 to 150!
Snonoby, what does
| CODE |
| int randomNumber = 50 + rand() % 51; |
do? ;)
However, there's a
variaty of reasons why one should
n't do rand() % NUMBER.
EDITED for stupid mistaked.
Rmstn1580 - January 4, 2007 07:43 AM (GMT)
Huh? I didn't read the whole post and I'm not good with random values :( Sorry. I've learned my lesson :)
ozgu - January 4, 2007 09:11 PM (GMT)
do {
x=50+rand()%100;
}while(x<100);
may this works...
myork - January 4, 2007 09:16 PM (GMT)
| QUOTE (ozgu @ Jan 4 2007, 04:11 PM) |
do {
x=50+rand()%100;
}while(x<100);
may this works... |
Why. Asked and answered by KTC.
| CODE |
| x=50+(rand() % 51); /* Note needs to be 51. If it was 50 the range would be 50 - 99 */ |
Shonoby - January 4, 2007 09:24 PM (GMT)
Ok, well i see what u all mean but i have already tried those example in one of my previous code my RPG text game, but the code is to big:
| CODE |
cout << "\nBOSS!!";
int HPGen = (700 + rand() % 1000 );
int StrGen = ( 100 + rand() % 120 );
int ExGen = ( 700 + rand() % 1000 );
if ( HPGen < 700 ) {
int y = 700;
int p;
p = y - HPGen;
HPGen += p;
}
if ( ExGen < 700 ) {
int z = 700;
int f;
f = z - ExGen;
ExGen += f;
|
To see the whole code just go to my signature 'my best work so far'.
Well as u can plainly see it is big, so it seem i stated my question in the wrong manner let me try again.
How can i make a rand() that is only one line or at least less than the one above,
that only gets numbers from value1 to value2 like so:
thats not a minues sign it means like only numbers from the first value to the second value. Thats just an example of what i mean, thats all i ask for if there is not than it does not matter i was just wondering
Zaqufant - January 4, 2007 11:47 PM (GMT)
Well, this was already posted, but what I think you want is this
| CODE |
| num=value1 + rand()%(value2-value1); |
sorta similar code. This assumes that value 2 is bigger than value 1. Hopes thats what you want.
Shonoby - January 4, 2007 11:56 PM (GMT)
Ohh yea, thxz man LOL so simple, i almost solved my own problem LOL thxz tho
Zaqufant - January 5, 2007 02:26 AM (GMT)
Any time. Any time at all.
latinos13 - January 10, 2007 02:17 PM (GMT)
hello!!i want to add a question...
When i use rand() in a for loop returns the same values every time i compile and run it...what's wrong??
e.g.
| CODE |
#include <cstdlib>
#include <iostream>
#include <windows.h>
using namespace std;
int main(){
int i;
for (i=1; i<=5; i++){
cout<< rand()%40+1 <<endl;
Sleep(1000);
}
return 0;
} |
myork - January 10, 2007 04:09 PM (GMT)
| QUOTE (latinos13 @ Jan 10 2007, 09:17 AM) |
hello!!i want to add a question...
When i use rand() in a for loop returns the same values every time i compile and run it...what's wrong??
e.g.
| CODE |
#include <cstdlib>
#include <iostream>
#include <windows.h>
using namespace std;
int main(){
int i;
for (i=1; i<=5; i++){
cout<< rand()%40+1 <<endl;
Sleep(1000);
}
return 0;
} |
|
So that you can debug a program the rand() function will return the same sequence of numbers each time. If you want to initialise the generation of a new sequence then you need to seed the generator with a start value. The best way to do this is:
| CODE |
int main()
{
srand(time(NULL)); |
time(NULL) returns the number of seconds since the epoch. So each time you run the program you will seed the random number generator with a new start point. rand() will then generate a new set of randome numbers.
