Script started on Mon Sep 15 17:27:35 2025
macbook:logs> cd ../programs/C_ch2
macbook:C_ch2> echo code for today is 461
code for today is 461
macbook:C_ch2> cat testfloat3b.c 
#include <stdio.h>

int main() {
    int v;

    v = 017;
    printf(" 017 Value is %d decimal \n", v);

    printf("v in octal is %o\n", v);
    return 0;
}

macbook:C_ch2> gcc testfloat3b.c 
macbook:C_ch2> ./a.out
 017 Value is 15 decimal 
v in octal is 17
macbook:C_ch2> vi simpleIO.c
macbook:C_ch2> gcc simpleIO.c
macbook:C_ch2> cat simpleIO.c
#include <stdio.h>

int main() {
  unsigned int u;

  printf("enter an unsigned int\n");
  scanf("%u", &u); 
  printf("Read this value: %u\n", u); 

  return 0;
}

macbook:C_ch2> ./a.out
enter an unsigned int
65
Read this value: 65
macbook:C_ch2> cat testchar.c
#include <stdio.h>

int main() {
    char ch;

    printf("Enter a char: ");
    scanf("%c", &ch);

    printf("You entered '%c' which is %d in decimal \n", ch, ch);
    return 0;
}

macbook:C_ch2> gcc  testchar.c 
macbook:C_ch2> ./a.out
Enter a char: 5
You entered '5' which is 53 in decimal 
macbook:C_ch2> ./a.out
Enter a char: x
You entered 'x' which is 120 in decimal 
macbook:C_ch2> ./a.out
Enter a char: a
You entered 'a' which is 97 in decimal 
macbook:C_ch2> ./a.out
Enter a char: A
You entered 'A' which is 65 in decimal 
macbook:C_ch2> ./a.out
Enter a char: 
You entered '
' which is 10 in decimal 
macbook:C_ch2> vi type_conv.c
macbook:C_ch2> gcc type_conv.c 
macbook:C_ch2> ./a.out
c is 3.550000
 d is 3
 %                                                                              macbook:C_ch2> cat type_conv.c 

#include <stdio.h>

int main() {

  int a=1, d=0;
  double b=2.55, c=0;
  c = a + b; // a is converted to double
  printf("c is %f\n ", c);
  d = a + b; //is illegal
  printf("d is %d\n ", d);

  return 0;
}

macbook:C_ch2> vi type_conv.c 
macbook:C_ch2> cat type_conv.c

#include <stdio.h>

int main() {

  int a=1, d=0;
  double b=2.55, c=0;
  c = a + b; // a is converted to double
  printf("c is %f\n ", c);
  d = a + b; //is illegal
  printf("d is %d\n", d);
  printf("\n");

  return 0;
}

macbook:C_ch2> gcc type_conv.c
macbook:C_ch2> ./a.out        
c is 3.550000
 d is 3

macbook:C_ch2> cat testfrac.c
#include <stdio.h>

int main() {
    char ch;
    float f, frac_part;

    f = 3.5;
  
    frac_part = f - (int)f;
    printf("frac_part = %f\n", frac_part);

    float quotient;
    int dividend = 7, divisor = 3;
    
    quotient = (float) dividend/ divisor;
    printf("quotient = %f\n", quotient);

    quotient = (float) (dividend/ divisor);
    printf("quotient = %f\n", quotient);

    return 0;
}

macbook:C_ch2> gcc testfrac.c
macbook:C_ch2> ./a.out
frac_part = 0.500000
quotient = 2.333333
quotient = 2.000000
macbook:C_ch2> cat typedef.c
/* 
  typedef allows for user-defined types
*/

#include <stdio.h>

typedef short int  Int16;

int main (void) {

   Int16 a = 4;

   printf("the number is %d\n", a); 

   return 0;
}


macbook:C_ch2> gcc typedef.c
macbook:C_ch2> ./a.out
the number is 4
macbook:C_ch2> cat typedef2.c 
/* 
  typedef allows for user-defined types
*/

#include <stdio.h>

typedef struct { int age; char *name; } person;

person people;

int main (void) {


   printf("this is a pertial example\n"); 

   return 0;
}


macbook:C_ch2> gcc typedef2.c
macbook:C_ch2> ./a.out
this is a pertial example
macbook:C_ch2> vi typedef2.c
macbook:C_ch2> cat typedef2.c
/* 
  typedef allows for user-defined types
*/

#include <stdio.h>

typedef struct { int age; char *name; } person;

person people;

int main (void) {


   printf("this is a partial example\n"); 

   return 0;
}


macbook:C_ch2> vi for_example.c
macbook:C_ch2> cat for_example.c 

#include <stdio.h>   

int main () {

  // Go through all possibilities
  for (int number=0; number<4; number++) {
/*
    switch (number) {
      case 0:
        printf("Zero\n");
        break;
      case 1:
        printf("One\n");
        break;
      case 2:
        printf("Two\n");
        break;
      default:
        printf("Expecting number to be 0, 1, or 2.\n");
      }
*/
    printf(" %d\n", number);
  }

  return 0;
}
macbook:C_ch2> gcc for_example.c 
macbook:C_ch2> ./a.out
 0
 1
 2
 3
macbook:C_ch2> vi switch_example.c
macbook:C_ch2> gcc switch_example.c
macbook:C_ch2> ./a.out 
Zero
One
Two
Expecting number to be 0, 1, or 2.
macbook:C_ch2> cat switch_example.c 
/* 
   Simple example showing a switch statement
   -MCW Sept. 2022
*/

#include <stdio.h>   

int main () {

  // Go through all possibilities
  for (int number=0; number<4; number++) {
    switch (number) {
      case 0:
        printf("Zero\n");
        break;
      case 1:
        printf("One\n");
        break;
      case 2:
        printf("Two\n");
        break;
      default:
        printf("Expecting number to be 0, 1, or 2.\n");
      }
    }

    return 0;
}
macbook:C_ch2> echo edit the program
edit the program
macbook:C_ch2> vi switch_example.c 
macbook:C_ch2> gcc switch_example.c 
macbook:C_ch2> cat switch_example.c 
/* 
   Simple example showing a switch statement
   -MCW Sept. 2022
*/

#include <stdio.h>   

int main () {

  // Go through all possibilities
  for (int number=0; number<4; number++) {
    switch (number) {
      case 0:
        printf("Zero\n");
        break;
      case 1:
        printf("One\n");
//        break;
      case 2:
        printf("Two\n");
        break;
      default:
        printf("Expecting number to be 0, 1, or 2.\n");
      }
    }

    return 0;
}
macbook:C_ch2> ./a.out
Zero
One
Two
Two
Expecting number to be 0, 1, or 2.
macbook:C_ch2> ls rand*
random_example.c
macbook:C_ch2> cat random_example.c
/* 
   Simple random number example
   -MCW Sept. 2022
   Updated to print 3 total random values in Sept 2024
*/

#include <stdio.h>   // input, output
#include <stdlib.h>  // for random, srandom
#include <math.h>    // for floor function
#include <time.h>    // for time function

int main () {

    // Call srandom to "seed" the random number generator.
    // See
    // https://stackoverflow.com/questions/16569239/how-to-use-
    //   function-srand-with-time-h
    // for more detail about srandom and time.
    // Basically, time returns a different value each time we run it.
    // Use it to give us a non-predictable sequence of random numbers.
    unsigned int mytime;   
    // get the current time
    mytime = time(NULL);

    // Seed the random number generator
    srandom(mytime);
 
    // random() returns a long integer.
    // Make sure to use random() instead of rand().
    // Use % (modulus) to reduce it to something manageable, 
    // in this case < 100.
    long r1 = random() % 100;

    // %li is for a long integer. %ld works too.
    printf("A random integer is %li.\n", r1);

    r1 = random() % 100;
    printf("A random integer is %li.\n", r1);
    r1 = random() % 100;
    printf("A random integer is %li.\n", r1);

    return 0;
}
macbook:C_ch2> gcc random_example.c 
macbook:C_ch2> ./a.out
A random integer is 44.
A random integer is 21.
A random integer is 45.
macbook:C_ch2> ./a.out
A random integer is 9.
A random integer is 18.
A random integer is 79.
macbook:C_ch2> ./a.out
A random integer is 86.
A random integer is 41.
A random integer is 24.
macbook:C_ch2> exit

Saving session...
...copying shared history...
...saving history...truncating history files...
...completed.

Script done on Mon Sep 15 18:44:06 2025