/* bufdemo.c
 * lecture slide 11 from CMU systems course at
 * https://www.cs.cmu.edu/afs/cs/academic/class/
 * 15213-f15/www/lectures/09-machine-advanced.pdf
 */

#include <stdio.h>

/* Get string from stdin ... an implementation of gets(). */
char* my_gets(char* dest) {
  char* p = dest;                  // p is pointer to start of destination.
  int c = getchar();               // Get a char from stdin.
  while (c != EOF && c != '\n') {  // Continue unless EndOfFile or newline.
    *p++ = c;                      //   Put char in buf then increment pointer.
    c = getchar();                 //   Get next character.
  }
  *p = '\0';                       // End of string; add null terminator.
  return dest;
} 

void echo(){
  // Quick quiz: how many characters can this buffer hold?
  char buf[4];   // Way too small!   (BTW, how big is big enough?)
  my_gets(buf);  // Read a string into the buffer.
  puts(buf);     // Print the string in the buffer.
}

void call_echo(){
  echo();
}

int main(){
  printf("Type a string: ");
  call_echo();
  return 0;
}