About random number in C (1 Viewer)

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i generate a sequence of random number in [0,9], and i need to know whether the random number is uniform or not, so i should check how many
time of 1 or 2 or 3....had been generated by the generator???
but my program is not work!!???

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
void main()
{
FILE*fptr;
char fname[]="SRN.txt";
int i,j,y,a[100];
fptr=fopen(fname,"w");
srand (time(NULL));
for(j=0;j<10;j++)
{
for(y=0,i=0;i<10;i++)
{
a=rand()%10;
if(j==a)y++;
printf("%d",a);
fprintf(fptr,"%d\n",y);
y=0;
}
}
fclose(fptr);
}

and how can i create a uniform ramdom number generator
 

Hurkyl

Staff Emeritus
Science Advisor
Gold Member
14,829
14
I don't think your problem is with C; I'm not entirely sure you know exactly what you're trying to do!

Try writing out in words what you are trying to do. Your goal is to write directions that are detailed enough that someone who has absolutely no idea what you're trying to do can follow the instructions.
 
if y is your random numbe ryou reset it everytime...that will probably be your problem. Actually its problably the problem anyways. There are several books out there for random generators, pick up sedgewick's text. I'm sure you can find a standard random generator formula...www.mathworld.com
 
353
0
generate a sequence of random number in [0,9], and i need to know whether the random number is uniform or not, so i should check how many
time of 1 or 2 or 3....had been generated by the generator???
but my program is not work!!???
int j;
int k;
int array[10]={0};
printf(" enter size");
scanf("%d", size);
for( i=0; i< size; i++);
{
j=rand( )% 10; /*there is got to be something more*/
array[j]++;
}
 
152
0
Thank you very much....
i know my ramdon generator is bad~~
i will find on some place...:smile:
 

jim mcnamara

Mentor
3,355
1,574
This article uses a tiny amount of math but is very clearly written:

http://www.eternallyconfuzzled.com/articles/rand.html [Broken]
 
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