Examples and points for attention about the use of getchar and scanf

// Examples of use ：
int main()
{
    
	// What we type on the keyboard is put in the buffer 
	//scanf and getchar Read from the buffer 
	char password[20] = {
     0 };
	printf(" Please input a password ：>");
	scanf("%s", password);//scanf Read the contents in the buffer , Read a space or \n end 
	// If you enter password There's a space in the middle , There is content after the space , such as abc ef
	//scanf Can only read to abc, And after reading , Automatically at the end c Add one at the end \0
	// So one getchar It can't be cleaned up abc What follows , Let's use a loop , All the way to \n End of carriage return 
	while (getchar() != '\n')
	{
    
		;
	}

	printf(" Please confirm the password （Y/N）：>");
	

	int ch = getchar();

	if (ch == 'Y')
	{
    
		printf(" Confirm success \n");
	}
	else
	{
    
		printf(" Confirmation failed \n");
	}

	return 0;
}