From e8186e657d51d9deedd171981d314933ed408db5 Mon Sep 17 00:00:00 2001
From: Akshay <nerdy@peppe.rs>
Date: Wed, 16 Dec 2020 16:05:10 +0530
Subject: add q3, q2, images

---
 q3/checksum.c |  37 +++++++++++++++++++++++++++++++++++++
 q3/checksum.o | Bin 0 -> 18600 bytes
 q3/hamming.c  |  56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 q3/hamming.o  | Bin 0 -> 18568 bytes
 4 files changed, 93 insertions(+)
 create mode 100644 q3/checksum.c
 create mode 100755 q3/checksum.o
 create mode 100644 q3/hamming.c
 create mode 100755 q3/hamming.o

(limited to 'q3')

diff --git a/q3/checksum.c b/q3/checksum.c
new file mode 100644
index 0000000..513ae17
--- /dev/null
+++ b/q3/checksum.c
@@ -0,0 +1,37 @@
+#include <stdio.h>
+#include <stdio.h>
+
+int checksum() {
+    unsigned int parts[9];
+    unsigned int sum;
+    printf("Enter the parts, one per line:\n");
+    for (int i = 0; i < 9; i++) {
+        scanf("%X", &parts[i]);
+        sum += parts[i];
+        while (sum >> 16)
+            sum = (sum & 0xffff) + (sum >> 16);
+    }
+    return ~sum;
+}
+
+int main() {
+    printf("--- SENDER ---\n");
+    int sender_checksum = checksum();
+    printf("\n--- RECV ---\n");
+    int recv_checksum = checksum();
+    printf("Sent checksum: %x\n", sender_checksum);
+    printf("Recieved checksum: %x\n", recv_checksum);
+    if (sender_checksum == recv_checksum) {
+        printf("Matching checksums!\n");
+        return 0;
+    } else {
+        printf("Mismatched checksums!\n");
+        return 0;
+    }
+}
+
+// 00004500 00000073 00000000 00004000 00004011 0000c0a8 00000001 0000c0a8 000000c7
+// checksum - ffffb861
+
+// 00004500 0000003c 00001c46 00004000 00004006 0000ac10 00000a63 0000ac10 00000a0c
+// checksum - 0000b1e6
diff --git a/q3/checksum.o b/q3/checksum.o
new file mode 100755
index 0000000..cfcaed6
Binary files /dev/null and b/q3/checksum.o differ
diff --git a/q3/hamming.c b/q3/hamming.c
new file mode 100644
index 0000000..01d0f0e
--- /dev/null
+++ b/q3/hamming.c
@@ -0,0 +1,56 @@
+#include<stdio.h>
+
+void main() {
+    int data[10];
+    int dataatrec[10],c,c1,c2,c3,i;
+
+    printf("Sender: ");
+    scanf("%d %d %d %d",&data[0] ,&data[1] ,&data[2] ,&data[4]);
+
+    //Calculation of even parity
+    data[6]=data[0]^data[2]^data[4];
+    data[5]=data[0]^data[1]^data[4];
+    data[3]=data[0]^data[1]^data[2];
+
+    printf("Encoded Data: ");
+    for(i=0;i<7;i++)
+        printf("%d",data[i]);
+
+    printf("\nReceiver: ");
+    for(i=0;i<7;i++)
+        scanf("%d",&dataatrec[i]);
+
+    c1=dataatrec[6]^dataatrec[4]^dataatrec[2]^dataatrec[0];
+    c2=dataatrec[5]^dataatrec[4]^dataatrec[1]^dataatrec[0];
+    c3=dataatrec[3]^dataatrec[2]^dataatrec[1]^dataatrec[0];
+    c=c3*4+c2*2+c1 ;
+
+    printf("\nSyndrome bits:  %d %d %d", c1, c2, c3);
+
+    if(c==0) {
+        printf("\nNo error while transmission of data\n");
+    }
+    else {
+        printf("\nError Position: %d",c);
+
+        printf("\nData sent: ");
+        for(i=0;i<7;i++)
+            printf("%d",data[i]);
+
+        printf("\nData received: ");
+        for(i=0;i<7;i++)
+            printf("%d",dataatrec[i]);
+
+        printf("\nCorrect message is: ");
+
+        //if errorneous bit is 0 we complement it else vice versa
+        if(dataatrec[7-c]==0)
+            dataatrec[7-c]=1;
+        else
+            dataatrec[7-c]=0;
+
+        for (i=0;i<7;i++) {
+            printf("%d",dataatrec[i]);
+        }
+    }
+}
diff --git a/q3/hamming.o b/q3/hamming.o
new file mode 100755
index 0000000..fa9cb70
Binary files /dev/null and b/q3/hamming.o differ
-- 
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