1 files changed, 49 insertions, 0 deletions
diff --git a/Q2.cpp b/Q2.cpp
new file mode 100644
index 0000000..956c343
--- /dev/null
+++ b/Q2.cpp
@@ -0,0 +1,49 @@
+
+#include <iostream>
+
+char *largestCommonSubstr(const char s1[], const char s2[]);
+
+using namespace std;
+int main(int argc, const char *argv[])
+{
+
+    const char *s1[] = {"Boston", "James", "computer" , "abc", "software"};
+    const char *s2[] = {"Killington", "Thames", "Counter", "abba", "MICROSOFT"};
+
+    for (int i = 0; i < 5; i++) {
+        char *substr = largestCommonSubstr(s1[i], s2[i]);
+        if (substr)
+            cout << "longest common substring of " << s1[i] << " and " << s2[i] << " is " << substr << endl;
+        else
+            cout << "no common substrings between " << s1[i] << " and " << s2[i] << endl;
+    }
+
+    return 0;
+}
+
+char *largestCommonSubstr(const char s1[], const char s2[])
+{
+    int len = 0;
+    int longest = 0;
+    int longestpos;
+    int pos1,pos2,ofst; 
+
+    for (pos1 = 0; s1[pos1]; pos1++) {
+        for (pos2 = 0; s2[pos2]; pos2++) {
+            for (ofst = 0,len=0; s1[pos1+ofst] == s2[pos2+ofst++]; len++) {}
+            if (len > longest) {
+                longest = len;
+                longestpos = pos1;
+            }
+        }
+    }
+    
+    char *result = longest != 0 ? new char(longest+1) : NULL;
+    if (result) {
+        for (int i = 0; i < longest; i++) {
+            result[i] = s1[longestpos+i];
+        }
+        result[longest] = '\0';
+    }
+    return result;
+}