Script started on Wed Sep 17 17:27:58 2025
macbook:logs> cd ../programs/C_ch3 
macbook:C_ch3> echo attend code: 7522
attend code: 7522
macbook:C_ch3> grep "10==9" *.c
expr.c:      a[i], (i%10==9||i==(n-1))?'E':'S');   // E for end, S for space
expr.c:      // a[i], (i%10==9||i==(n-1))?'\n':' '); 
macbook:C_ch3> cat expr.c
/* 
  expr1? expr2 : expr3 example

  (Unsure of source: Probably King's C book, chapter 3)
*/

#include <stdio.h>

int main () {

  int i;
  int a[] = { 23, 34, 45, 56, 67, 78, 89, 90, 01, 12, 4, 3, 2, 1 };
  int n = 14;

  for (i=0; i<n; i++) { 
    printf("%6d %c", 
      a[i], (i%10==9||i==(n-1))?'E':'S');   // E for end, S for space
      // a[i], (i%10==9||i==(n-1))?'\n':' '); 
  } 

  return 0;
}
macbook:C_ch3> gccc expr.c
zsh: command not found: gccc
macbook:C_ch3> gcc expr.c 
macbook:C_ch3> ./a.out
    23 S    34 S    45 S    56 S    67 S    78 S    89 S    90 S     1 S    12 E     4 S     3 S     2 S     1 E%                                               macbook:C_ch3> vi expr.c 
macbook:C_ch3> cat expr.c 
/* 
  expr1? expr2 : expr3 example

  (Unsure of source: Probably King's C book, chapter 3)
*/

#include <stdio.h>

int main () {

  int i;
  int a[] = { 23, 34, 45, 56, 67, 78, 89, 90, 01, 12, 4, 3, 2, 1 };
  int n = 14;

  for (i=0; i<n; i++) { 
    printf("%6d %c", 
      // a[i], (i%10==9||i==(n-1))?'E':'S');   // E for end, S for space
      a[i], (i%10==9||i==(n-1))?'\n':' '); 
  } 
  printf("\n");

  return 0;
}
macbook:C_ch3> gcc expr.c 
macbook:C_ch3> ./a.out
    23      34      45      56      67      78      89      90       1      12 
     4       3       2       1 

macbook:C_ch3> vi Sept17_example.txt
macbook:C_ch3> cp ../C_ch2/hello.c bitwise_AND.c
macbook:C_ch3> vi bitwise_AND.c 
macbook:C_ch3> gcc bitwise_AND.c
macbook:C_ch3> cat bitwise_AND.c
/* 
  bitwise_AND.c
*/

#include <stdio.h>

int main (int argc, char *argv[]) {
   int a = 3;
   int b = 6;
   int c;

   c = a & b;
   printf("%d & %d = %d\n", a, b, c); 

   return 0;
}
macbook:C_ch3> ./a.out
3 & 6 = 2
macbook:C_ch3> cat Sept17_example.txt
3 = 0011
6 = 0110  &
  ---------
    0010


macbook:C_ch3> vi bitwise_AND.c 
macbook:C_ch3> gcc bitwise_AND.c     
macbook:C_ch3> cat bitwise_AND.c   
/* 
  bitwise_AND.c
*/

#include <stdio.h>

int main (int argc, char *argv[]) {
   int a = 3;
   int b = 6;
   int c;

   c = a & b;
   printf("%d & %d = %d\n", a, b, c); 

   if (a && b)
     printf("a && b true\n");
   else
     printf("a && b false\n");

   return 0;
}
macbook:C_ch3> ./a.out
3 & 6 = 2
a && b true
macbook:C_ch3> echo 1 is 0001, 2 is 0010 
1 is 0001, 2 is 0010
macbook:C_ch3> vi Sept17_example_2.txt
macbook:C_ch3> cat Sept17_example_2.txt 

OR truth table
   
   x y | x OR y
  -------------
   0 0 |   0
   0 1 |   1
   1 0 |   1
   1 1 |   1


x = 1 = 0001
y = 2 = 0010 |   (bitwise OR)
        ------ 
        0011   = 3


convert 0 0 1 1 to decimal
              1x2^0
            1x2^1
          0x2^2 
        0x2^3 
add these = 0x2^3 + 0x2^2 + 1x2^1 + 1x2^0 = 0 + 0 + 2 + 1 = 3

macbook:C_ch3> exit

Saving session...
...copying shared history...
...saving history...truncating history files...
...completed.
Deleting expired sessions...none found.

Script done on Wed Sep 17 18:45:32 2025