Which of the following declaration is not supported by C language?String str;Both “String str;” and “float str = 3e2;”float str = 3e2;char *str;

Break Down the Problem

1. Identify each declaration in the question and determine if it is valid in C language.
2. Understand the rules for variable declarations in C.

Relevant Concepts

1. Variable Declaration: C language has specific rules for declaring variables, including type names.
2. Data Types: Standard data types in C include int, float, char, etc. User-defined types such as String are not part of standard C.

Analysis and Detail

1. String str;:

   • "String" is not a standard data type in C. C does not have a built-in string type; it uses character arrays or pointers for strings.

2. float str = 3e2;:

   • This declaration is valid. It initializes str as a float with the value 300.0.

3. char *str;:

   • This is a valid declaration as it declares a pointer to a char, which can also be used to point to strings (character arrays).

Verify and Summarize

• The analysis shows that only the first declaration, "String str;", is not valid in C. Both the second declaration and the third declaration are supported by C.

Final Answer

The declaration that is not supported by C language is "String str;".