Create swapdoublebytes.c

swapdoublebytes.c

@@ -0,0 +1,48 @@
+#include <stdio.h>
+
+/*
+ * Print the bits in n in four formats:
+ *
+ * hexadecimal
+ * decimal with bits interpreted as signed int.
+ * decimal with bits interpreted as unsigned int.
+ * binary
+ */
+void print_bits(int n)
+{
+    // print the integer in different format
+    printf("hex:%08X signed:%d unsigned:%u bits:", n, n, n);
+
+    // a loop to print bits from most significant to least significant
+    // also an example of sizeof use
+    for (int i = sizeof(int) * 8 - 1; i >= 0; i --)
+       printf("%d", (n >> i) & 1);
+    printf("\n");
+}
+
+int main()
+{
+    int n;
+
+    // Repeatedly read an integer 'n' from standard input and
+    // swap left and right double bytes into 'n1' if successful.
+    // To exit, press Ctrl-D or Ctr-C
+    while (scanf("%d", &n) == 1) {
+
+            int n1 = 0;
+            int firsthalf =  (n &0xFFFF0000) >> 16;
+            int secondhalf = (n &0x0000FFFF) << 16;
+
+            n1 = (firsthalf|secondhalf);
+
+        // Your code to swap left and right double bytes in n and 
+        // save the changed value in n1.
+        // call function to print the bits in n and n1
+
+        print_bits(n);
+        print_bits(n1);
+    }
+
+    /* Let the OS know everything is just peachy. */
+    return 0;
+}