rajabishek · November 1, 2015 17:32 · Nov 1, 2015
diff --git a/crc.c b/crc.c
@@ -0,0 +1,64 @@
+#include<stdio.h>
+#include<string.h>
+#define N strlen(g)
+
+char t[28],cs[28],g[]="1011";
+int a,e,c;
+
+void xorfunction(){
+    for(c = 1;c < N; c++)
+    cs[c] = (( cs[c] == g[c])?'0':'1');
+}
+
+void crc(){
+    for(e=0;e<N;e++)
+        cs[e]=t[e];
+    do{
+        if(cs[0]=='1')
+            xorfunction();
+        for(c=0;c<N-1;c++)
+            cs[c]=cs[c+1];
+        cs[c]=t[e++];
+    }while(e<=a+N-1);
+}
+
+int main()
+{
+    printf("\nEnter data : ");
+    scanf("%s",t);
+    printf("\n----------------------------------------");
+    printf("\nGenerating polynomial : %s",g);
+    a=strlen(t);
+    for(e=a;e<a+N-1;e++)
+        t[e]='0';
+    printf("\n----------------------------------------");
+    printf("\nPaded data is : %s",t);
+    printf("\n----------------------------------------");
+    crc();
+    printf("\nCRC is : %s",cs);
+    for(e=a;e<a+N-1;e++)
+        t[e]=cs[e-a];
+    printf("\n----------------------------------------");
+    printf("\nFinal data to be sent : %s",t);
+    printf("\n----------------------------------------");
+    printf("\nTest error detection 0(yes) 1(no)? : ");
+    scanf("%d",&e);
+    if(e==0)
+    {
+        do{
+            printf("\nEnter the position where error is to be inserted : ");
+            scanf("%d",&e);
+        }while(e==0 || e>a+N-1);
+        t[e-1]=(t[e-1]=='0')?'1':'0';
+        printf("\n----------------------------------------");
+        printf("\nErroneous data : %s\n",t);
+    }
+    crc();
+    for(e=0;(e<N-1) && (cs[e]!='1');e++);
+        if(e<N-1)
+            printf("\nError detected\n\n");
+        else
+            printf("\nNo error detected\n\n");
+            printf("\n----------------------------------------\n");
+        return 0;
+}