How to stop user entering char as int input in C

Question

Heres a part of my code:

    printf(\"\\nEnter amount of adult tickets:\");
    scanf(\"%d\", &TktAdult);
    while (TktAdult<0){
        printf(\"\\n         


        

Answer 1

The following code rejects user input that are:

• non-numeric as handled by // 1;
• negative numbers as handled by // 2;

• positive numbers followed by non-numeric chars as handled by //3

  while (1) {
      printf("\nEnter amount of adult tickets: ");
      if (scanf("%d", &TktAdult) < 0 ||  // 1
              TktAdult < 0 ||  // 2
              ((next = getchar()) != EOF && next != '\n')) {  // 3
          clearerr(stdin);
          do
              next = getchar();
          while (next != EOF && next != '\n');  // 4
          clearerr(stdin);
          printf("\nPlease enter a positive number!");
      } else {
          break;
      }
  }
  

Also, // 4 clears the standard input of buffered non-numeric characters following case // 3 (i.e. 123sda - scanf takes 123 but leaves 'sda' in the buffer).