Work on exercises 2-7 and 2-8 then move on to 2.10 Assignment Operators and Expressions

ch_02/bitwise_operators/main.c

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+/*
+ *
+ * This program briefly demonstrates usage of bitwise operators.
+ *
+ * Author: Kun Deng
+ *
+ */
+
+#include <stdio.h>
+
+
+int main()
+{
+    // 500 in binary is 111110100
+    int n = 500;
+
+    printf("n is %d\n", n);
+
+    int n_temp = n;
+    // Octal value 0177 is 127 in numerical form or 001111111 in binary
+    int nb = 0177;
+    // The result is 116 or 001110100 in binary
+    // Bits are compared and if both aren't on then they get turned off
+    // 500 - 111110100
+    // 127 - 001111111
+    // ---------------
+    // 116 - 001110100
+    n = n & nb;
+
+    printf("%d & 0177 = %d\n", n_temp,  n);
+
+    n = n_temp;
+    // 63 in binary is 0111111
+    int nc = 63;
+
+    // The result is 511 or 111111111 in binary
+    // Bits are compared and if any are on then the result gets turned on
+    // 500 - 111110100
+    //  63 -    111111
+    // ---------------
+    // 511 - 111111111
+    n = n | nc;
+
+    printf("%d | %d = %d\n", n_temp, nc, n);
+
+    n = n_temp;
+    // The result is 459 or 111111111 in binary
+    // Bits are compared and if they differ then they are turned on. If
+    // they are the same then they are turned off
+    // 500 - 111110100
+    //  63 -    111111
+    // ---------------
+    // 459 - 111001011
+    n = n ^ nc;
+
+    printf("%d ^ %d = %d\n", n_temp, nc, n);
+
+    n = n_temp;
+    // 6 is 110 in binary
+    int nd = 6;
+
+    // The result is 32000 or 111110100000000 in binary
+    // The bits were shifted left by 6 positions and the vacancies
+    // were populated with zeros
+    //   500 -       111110100
+    //     6 -             110
+    // -----------------------
+    // 32000 - 111110100000000
+    n = n << nd;
+
+    printf("%d << %d = %d\n", n_temp, nd, n);
+
+    n = n_temp;
+    // 3 is 11 in binary
+    int ne = 3;
+
+    // The result is 62 or 111110 in binary
+    // The bits were shifted right by 3 positions
+    //   500 -       111110100
+    //     3 -              11
+    // -----------------------
+    //    62 -          111110
+    n = n >> ne;
+
+    printf("%d >> %d = %d\n", n_temp, ne, n);
+
+    n = n_temp;
+    // Octal value 025 is 21 in numerical form and 10101 in binary
+    int nf = 025;
+
+    // The result is 480 or 111110000 in binary
+    // After the one's complement of octal value 025 was taken,
+    // the one's complement of that was compared with 500, bit by
+    // bit. When bits didn't match, they got turned off.
+    //   500 -       111110100
+    //   ~21 -            1010
+    // -----------------------
+    //   480 -       111110000
+    n = n & ~nf;
+
+    printf("%d & ~025 = %d\n", n_temp, n);
+
+    return 0;
+}