Generate a RANDOM NO. in a given RANGE – C PROGRAM

In the last few posts I have written about generating random numbers and using them to simulate a coin flip or a 1-d random walk.
In this post I will show you how to generate a random number in a given range.

CODE:

/**********************************************
****GENERATE RANDOM NUMBERS IN A GIVEN RANGE***
***********************************************/
#include<stdio.h>
#include<math.h>
/**Function that generates a random number.
Parameters: 
r0: initial (first) seed
a: scale factor , so that a*r0 give the first random number
m: gives the max. value of random numbers that can be generated (m-1)
c: additional displacement(offset) factor
**/
int rand(int r0, int a, int m, int c){
	int r1=(a*r0+c)%m;
	return r1;
}
/**Function that generates random numbers in a given range: [min,max], given a seed r0, and stores them in an array that is passed as an argument.
Parameters:
r0: initial (first) seed
a: scale factor , so that a*r0 give the first random number
m: gives the max. value of random numbers that can be generated (m-1)
c: additional displacement factor
n: no. of random numbers to be generated
x[n]: array that will store the random numbers
min: lower limit for random nos.
max: upper limit for random nos.
**/
void randomNos(int r0, int a, int m, int c, int n, int x[n], int min, int max){
	int r1=rand(r0,a,m,c);
	int r2=min+((max-min+1)*r1)/m;
	int i;
	for(i=0;i<n;i++){
		x[i]=r2;
		r1=rand(r1,a,m,c);
		r2=min+((max-min+1)*r1)/m;
	}
}
main(){
	int min, max, n, a=1093, m=86436, c=18257, r0=43;
	printf("Enter the lower limit:\n");
	scanf("%d",&min);
	printf("Enter the higher limit:\n");
	scanf("%d",&max);
	printf("Enter the no. of random numbers required:\n");
	scanf("%d",&n);
	int random[n];
	randomNos(r0, a, m, c, n, random, min, max);
	int i;
	printf("The random numbers between %d and %d are:\n",min, max);
	for(i=0;i<n;i++){
		printf("%d\n",random[i]);
	}
}

OUTPUT:

Sample run 1

[wpedon id="7041" align="center"]

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