<P> In static typing, all expressions have their types determined prior to when the program is executed, typically at compile - time . For example, 1 and (2 + 2) are integer expressions; they cannot be passed to a function that expects a string, or stored in a variable that is defined to hold dates . </P> <P> Statically typed languages can be either manifestly typed or type - inferred . In the first case, the programmer must explicitly write types at certain textual positions (for example, at variable declarations). In the second case, the compiler infers the types of expressions and declarations based on context . Most mainstream statically typed languages, such as C++, C#and Java, are manifestly typed . Complete type inference has traditionally been associated with less mainstream languages, such as Haskell and ML . However, many manifestly typed languages support partial type inference; for example, C++, Java and C#all infer types in certain limited cases . Additionally, some programming languages allow for some types to be automatically converted to other types; for example, an int can be used where the program expects a float . </P> <P> Dynamic typing, also called latent typing, determines the type - safety of operations at run time; in other words, types are associated with run - time values rather than textual expressions . As with type - inferred languages, dynamically typed languages do not require the programmer to write explicit type annotations on expressions . Among other things, this may permit a single variable to refer to values of different types at different points in the program execution . However, type errors cannot be automatically detected until a piece of code is actually executed, potentially making debugging more difficult . Lisp, Smalltalk, Perl, Python, JavaScript, and Ruby are all examples of dynamically typed languages . </P> <P> Weak typing allows a value of one type to be treated as another, for example treating a string as a number . This can occasionally be useful, but it can also allow some kinds of program faults to go undetected at compile time and even at run time . </P>

Discuss the important of programming language to digital computer