C - compare 2 char

 #include <stdio.h>
 int main()
 {
 char a,b;
 printf("Which character is greater?\n");
 printf("Type a single character:");
 a=getchar();
 printf("Type another character:");
 b=getchar();
 if(a > b)
 {
 printf("‘%c’ is greater than ‘%c’!\n",a,b);
 }
 else if (b > a)
 {
 printf("‘%c’ is greater than ‘%c’!\n",b,a);
 }
 else
 {
 printf("Next time, don’t type the same character twice.");
 }
 return(0);
 }

this is code is from the book " C for dummies "

the characters are compared by an if statement as well as by if-else. The greater of the two is then displayed.

the program gets compiled, but executing it, afhter the first simbol imputed skips to the IF statement, skping the 2'nd getchar. this way the items fail to compare.

where is the bug ? thank you