Create rabinkarp.cpp

rabinkarp.cpp

@@ -0,0 +1,66 @@
+#include <iostream>
+#include <string.h>
+using namespace std;
+
+#define d 256
+
+void search(char pat[], char txt[], int q)
+{
+    int M = strlen(pat);
+    int N = strlen(txt);
+    int i, j;
+    int p = 0; 
+    int t = 0; 
+    int h = 1;
+
+    for (i = 0; i < M - 1; i++)
+        h = (h * d) % q;
+
+    for (i = 0; i < M; i++)
+    {
+        p = (d * p + pat[i]) % q;
+        t = (d * t + txt[i]) % q;
+    }
+
+    for (i = 0; i <= N - M; i++)
+    {
+        if ( p == t )
+        {  
+            bool flag = true;
+
+            for (j = 0; j < M; j++)
+            {
+                if (txt[i+j] != pat[j])
+                {
+                  flag = false;
+                  break;
+                }     
+            }
+
+            if (j == M)
+                cout<<"Pattern found at index "<< i<<endl;
+        }
+
+        if ( i < N-M )
+        {
+            t = (d*(t - txt[i]*h) + txt[i+M])%q;
+            if (t < 0)
+            	t = (t + q);
+        }
+    }
+}
+
+int main()
+{
+    char txt[100];
+    char pat[100];
+    int q=101;
+
+	cout<<"Enter string: ";
+	cin.getline(txt,100);  
+	cout<<"Enter pattern to be searched: "; 
+    cin.getline(pat,100);
+
+    search(pat, txt, q);
+    return 0;
+}