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]); } }