On line 14 use && (and) operator instead || (or) operator. You want to find out if str is not equal to str1 AND if it is not equal to str2.
But strcmp() does a case sensitive comparison, meaning that Yes is not the same as yes or yEs or yeS. You should use a case insensitive comparison. One such function is stricmp(), which may not be available on all compilers. Another way to do that is to convert the entire string to either upper or lower case, depending on the string that you want to compare it with. To do that just loop through the string and call toupper() or tolower() for each character.