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

... stop user from entering a negative value ...

is not possible. Users enter all sorts of gibberish. Instead, read a line of user input and parse it for correctness. Use fgets() for input, then sscanf(), strtol(), etc. for parsing.

// return -1 on EOF
int GetPositiveNumber(const char *prompt, const char *reprompt) {
  char buf[100];
  fputs(prompt, stdout);
  fflush(stdout);
  while (fgets(buf, sizeof buf, stdin)) [
    int value;
    if (sscanf(buf, "%d", &value) == 1 && value > 0) {
      return value;
    }
    fputs(reprompt, stdout);
    fflush(stdout);
  }
  return -1;
}

// Usage
int TktAdult = GetPositiveNumber(
    "\nEnter amount of adult tickets:" , 
    "\nPlease enter a positive number!");
if (TktAdult < 0) Handle_End_of_File();
else Success(TktAdult);