In C, "=" is an assignment operator, not a comparison. To compare values, you need to us "==" instead:
if((a=1 && ac-10 && b='A' &&bes'C'))
Becomes:
if((a==1 && ac-10 && b=='A' &&bes'C'))
????? ??????
Quite what you meant the bits with question marks below them to be is anyone's guess! Certainly, I have no idea ...
To check is a number is greater than another, use this:
x >= y
which is true if
x
is the same as or larger than
y
.
To check is a number is less than another, use this:
x <= y
which is true if
x
is the same as or less than
y
.