The following piece of code encrypts the line of text taken as input by shifting each character of the line by a key value. It uses the index notation. (Assume MAX is a #define constant.)

  char line[MAX]; 
  int i = 0, key = 4;
  printf("Enter a line of text:");
  scanf("%[^\n]", line);
  while (line[i])
  { 
    putchar(line[i]+key);
    i++;
  }

In an attempt to rewrite the entire code using pointer notation, a beginner program made the following attempt:

  char line[MAX];
  int key = 4;
  printf("Enter a line of text: ");
  scanf("%[^\n]", line);
  while (*line)
  {
    putchar(*line + key);
    line++;
  }

Unfortunately, the code would not compile. Can you find the mistake and fix it? You do not have to rewrite the entire code segment, but only the parts you are modifying.