C Program for Rabin-Karp String Matching Algorithm

#include <stdio.h>
#include <stdlib.h>
#include<string.h>
int main()
{
printf("\t\tRABIN KARP ALGORITHM\n");
char a[] = "Hello World" ;
char b[] = "World" ;
int la = strlen(a);
int lb = strlen(b);
int d = 100,p=0,t=0,h=1,i,j,mod = 101;
for(i=0;i<lb-1;i++)
h=(d*h)%mod;
for(i=0;i<lb;i++)
{
p = (d*p + b[i])%mod;
t = (d*t + a[i])%mod;
}
for(i=0;i<=la-lb;i++)
{ if(p==t)
{
for(j=0;j<lb;j++)
{
if(a[i+j]!=b[j])
break;
}
if(j==lb)
printf("pattern found at %d",i+1);
}
if(i<la-lb)
{
t = (d*(t - a[i]*h) + a[i+lb])%mod;
if(t < 0)
t = (t + mod);
}
}
return 0;
}