Last login: Mon Apr  3 10:09:05 2017 from 198.0.135.11
[cs50@flume ~]$ cd demo
[cs50@flume ~/demo]$ ls
[cs50@flume ~/demo]$ ls
[cs50@flume ~/demo]$ emacs guessprime.c
[cs50@flume ~/demo]$ cat guessprime.c ; mygcc guessprime.c -o guessprime
/* 
 * guessprime - a little game where user must guess a prime number
 *
 * David Kotz April 2017
 */

// one-line comments
/* longer comments */

int main()
{
  const int answer = 31;
  int guess;

  printf("Enter a prime number (1 to 100): ");
  scanf("%d", &guess);

  while (guess != answer) {
    printf("wrong!");
    printf("Enter a prime number (1 to 100): ");
    scanf("%d", &guess);
  }

  return 0;
}
guessprime.c: In function ‘main’:
guessprime.c:15:3: warning: implicit declaration of function ‘printf’ [-Wimplicit-function-declaration]
   printf("Enter a prime number (1 to 100): ");
   ^~~~~~
guessprime.c:15:3: warning: incompatible implicit declaration of built-in function ‘printf’
guessprime.c:15:3: note: include ‘<stdio.h>’ or provide a declaration of ‘print’
guessprime.c:16:3: warning: implicit declaration of function ‘scanf’ [-Wimplicit-function-declaration]
   scanf("%d", &guess);
   ^~~~~
guessprime.c:16:3: warning: incompatible implicit declaration of built-in function ‘scanf’
guessprime.c:16:3: note: include ‘<stdio.h>’ or provide a declaration of ‘scanf’
[cs50@flume ~/demo]$ emacs guessprime.c
[cs50@flume ~/demo]$ cat guessprime.c ; mygcc guessprime.c -o guessprime
/* 
 * guessprime - a little game where user must guess a prime number
 *
 * David Kotz April 2017
 */

#include <stdio.h>
#include <stdlib.h>

int main()
{
  const int answer = 31;
  int guess;

  printf("Enter a prime number (1 to 100): ");
  scanf("%d", &guess);

  while (guess != answer) {
    printf("wrong!");
    printf("Enter a prime number (1 to 100): ");
    scanf("%d", &guess);
  }

  return 0;
}
[cs50@flume ~/demo]$ ls -l
total 20
-rwxr-xr-x 1 cs50 cs50 11136 Apr  3 14:26 guessprime*
-rw-r--r-- 1 cs50 cs50   410 Apr  3 14:25 guessprime.c
-rw-r--r-- 1 cs50 cs50   414 Apr  3 14:22 guessprime.c~
[cs50@flume ~/demo]$ ./guessprime 
Enter a prime number (1 to 100): 7
wrong!Enter a prime number (1 to 100): 2
wrong!Enter a prime number (1 to 100): 5
wrong!Enter a prime number (1 to 100): 31
[cs50@flume ~/demo]$ !ema
emacs guessprime.c
[cs50@flume ~/demo]$ cat guessprime.c ; mygcc guessprime.c -o guessprime
/* 
 * guessprime - a little game where user must guess a prime number
 *
 * David Kotz April 2017
 */

#include <stdio.h>
#include <stdlib.h>

int main()
{
  const int answer = 31;
  int guess;

  printf("Enter a prime number (1 to 100): ");
  scanf("%d", &guess);

  while (guess != answer) {
    printf("wrong!\n\n");
    printf("Enter a prime number (1 to 100): ");
    scanf("%d", &guess);
  }

  return 0;
}
[cs50@flume ~/demo]$ ./guessprime 
Enter a prime number (1 to 100): 34344
wrong!

Enter a prime number (1 to 100): 3
wrong!

Enter a prime number (1 to 100): 31
[cs50@flume ~/demo]$ emacs guessprime.c
[cs50@flume ~/demo]$ cat guessprime.c ; mygcc guessprime.c -o guessprime
/* 
 * guessprime - a little game where user must guess a prime number
 *
 * David Kotz April 2017
 */

#include <stdio.h>
#include <stdlib.h>

int readGuess()
{
  int guess;
  
  printf("Enter a prime number (1 to 100): ");
  scanf("%d", &guess);

  return guess;
}

int main()
{
  const int answer = 31;
  int guess;

  guess = readGuess();
  
  while (guess != answer) {
    printf("wrong!\n\n");
    guess = readGuess();
  }

  return 0;
}
[cs50@flume ~/demo]$ ./guessprime 
Enter a prime number (1 to 100): 3
wrong!

Enter a prime number (1 to 100): 4
wrong!

Enter a prime number (1 to 100): 31
[cs50@flume ~/demo]$ emacs guessprime.c
[cs50@flume ~/demo]$ cat guessprime.c ; mygcc guessprime.c -o guessprime
/* 
 * guessprime - a little game where user must guess a prime number
 *
 * David Kotz April 2017
 */

#include <stdio.h>
#include <stdlib.h>

int main()
{
  const int answer = 31;
  int guess;

  guess = readGuess();
  
  while (guess != answer) {
    printf("wrong!\n\n");
    guess = readGuess();
  }

  return 0;
}

int readGuess()
{
  int guess;
  
  printf("Enter a prime number (1 to 100): ");
  scanf("%d", &guess);

  return guess;
}

guessprime.c: In function ‘main’:
guessprime.c:15:11: warning: implicit declaration of function ‘readGuess’ [-Wimplicit-function-declaration]
   guess = readGuess();
           ^~~~~~~~~
[cs50@flume ~/demo]$ !em
emacs guessprime.c
[cs50@flume ~/demo]$ cat guessprime.c ; mygcc guessprime.c -o guessprime
/* 
 * guessprime - a little game where user must guess a prime number
 *
 * David Kotz April 2017
 */

#include <stdio.h>
#include <stdlib.h>

/* function prototype */
int readGuess();

/* main */
int main()
{
  const int answer = 31;
  int guess;

  guess = readGuess();
  
  while (guess != answer) {
    printf("wrong!\n\n");
    guess = readGuess();
  }

  return 0;
}

/* readGuess */
/* function definition */
int readGuess()
{
  int guess;
  
  printf("Enter a prime number (1 to 100): ");
  scanf("%d", &guess);

  return guess;
}

[cs50@flume ~/demo]$ ./guessprime 
Enter a prime number (1 to 100): 3
wrong!

Enter a prime number (1 to 100): 2
wrong!

Enter a prime number (1 to 100): 31
[cs50@flume ~/demo]$ !em
emacs guessprime.c
[cs50@flume ~/demo]$ cat guessprime.c ; mygcc guessprime.c -o guessprime
/* 
 * guessprime - a little game where user must guess a prime number
 *
 * David Kotz April 2017
 */

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

/* function prototype */
int readGuess();
bool isPrime(const int n);

/* main */
int main()
{
  const int answer = 31;
  int guess;

  guess = readGuess();
  
  while (guess != answer) {
    printf("wrong!\n\n");
    guess = readGuess();

    if (guess < 0 || guess > 100) {
      printf("guess %d is out of range!\n", guess);
    }

    if (!isPrime(guess)) {
      printf("guess %d is not even prime!\n", guess);
    }
  }

  return 0;
}

/* readGuess */
/* function definition */
int readGuess()
{
  int guess;
  
  printf("Enter a prime number (1 to 100): ");
  scanf("%d", &guess);

  return guess;
}

/* isPrime */
bool isPrime(const int n)
{
  if (n < 2) return false;
  if (n > 2 && n%2 == 0) return false;
  if (n > 3 && n%3 == 0) return false;
  if (n > 5 && n%5 == 0) return false;
  if (n > 7 && n%7 == 0) return false;
  return true;
}
[cs50@flume ~/demo]$ ./guessprime 
Enter a prime number (1 to 100): 3
wrong!

Enter a prime number (1 to 100): 4
guess 4 is not even prime!
wrong!

Enter a prime number (1 to 100): 0
guess 0 is not even prime!
wrong!

Enter a prime number (1 to 100): -1
guess -1 is out of range!
guess -1 is not even prime!
wrong!

Enter a prime number (1 to 100): 9999
guess 9999 is out of range!
guess 9999 is not even prime!
wrong!

Enter a prime number (1 to 100): 100
guess 100 is not even prime!
wrong!

Enter a prime number (1 to 100): 31
[cs50@flume ~/demo]$ fg
-bash: fg: current: no such job
[cs50@flume ~/demo]$ !em
emacs guessprime.c
[cs50@flume ~/demo]$ cat guessprime.c ; mygcc guessprime.c -o guessprime
/* 
 * guessprime - a little game where user must guess a prime number
 *
 * David Kotz April 2017
 */

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

/* function prototype */
int readGuess();
bool isPrime(const int n);

/* main */
int main()
{
  const int answer = 31;
  int guess;

  guess = readGuess();
  
  while (guess != answer) {
    printf("wrong!\n\n");
    guess = readGuess();
  }

  return 0;
}

/* readGuess */
/* function definition */
int readGuess()
{
  int guess;
  
  printf("Enter a prime number (1 to 100): ");
  scanf("%d", &guess);

  if (guess < 0 || guess > 100) {
    printf("guess %d is out of range!\n", guess);
  }
  
  if (!isPrime(guess)) {
    printf("guess %d is not even prime!\n", guess);
  }
  
  return guess;
}

/* isPrime */
bool isPrime(const int n)
{
  if (n < 2) return false;
  if (n > 2 && n%2 == 0) return false;
  if (n > 3 && n%3 == 0) return false;
  if (n > 5 && n%5 == 0) return false;
  if (n > 7 && n%7 == 0) return false;
  return true;
}
[cs50@flume ~/demo]$ ./guessprime 
Enter a prime number (1 to 100): 4
guess 4 is not even prime!
wrong!

Enter a prime number (1 to 100): 31
[cs50@flume ~/demo]$ fg
-bash: fg: current: no such job
[cs50@flume ~/demo]$ fg
-bash: fg: current: no such job
[cs50@flume ~/demo]$ !em
emacs guessprime.c
[cs50@flume ~/demo]$ cat guessprime.c ; mygcc guessprime.c -o guessprime
/* 
 * guessprime - a little game where user must guess a prime number
 *
 * David Kotz April 2017
 */

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

/* function prototype */
int readGuess();
bool isPrime(const int n);
int pickPrime(const int max);

/* main */
int main()
{
  const int answer = pickPrime(100);
  int guess;

  guess = readGuess();
  
  while (guess != answer) {
    printf("wrong!\n\n");
    guess = readGuess();
  }

  return 0;
}

/* readGuess */
/* function definition */
int readGuess()
{
  int guess;
  
  printf("Enter a prime number (1 to 100): ");
  scanf("%d", &guess);

  if (guess < 0 || guess > 100) {
    printf("guess %d is out of range!\n", guess);
  }
  
  if (!isPrime(guess)) {
    printf("guess %d is not even prime!\n", guess);
  }
  
  return guess;
}

/* isPrime */
bool isPrime(const int n)
{
  if (n < 2) return false;
  if (n > 2 && n%2 == 0) return false;
  if (n > 3 && n%3 == 0) return false;
  if (n > 5 && n%5 == 0) return false;
  if (n > 7 && n%7 == 0) return false;
  return true;
}

int pickPrime(const int max)
{
  int p;

  for (p = 0; !isPrime(p); p = (rand() % max + 1)) {
    ; // keep looking!
  }

  return p;
}

[cs50@flume ~/demo]$ ./guessprime 
Enter a prime number (1 to 100): 31
wrong!

Enter a prime number (1 to 100): 7
wrong!

Enter a prime number (1 to 100): 3
wrong!

Enter a prime number (1 to 100): 5
wrong!

Enter a prime number (1 to 100): 2
wrong!

Enter a prime number (1 to 100): 27
guess 27 is not even prime!
wrong!

Enter a prime number (1 to 100): 24
guess 24 is not even prime!
wrong!

Enter a prime number (1 to 100): 23
wrong!

Enter a prime number (1 to 100): 0
guess 0 is not even prime!
wrong!

Enter a prime number (1 to 100): ^C
[cs50@flume ~/demo]$ packet_write_wait: Connection to 129.170.214.115 port 22: Broken pipe

[Process completed]