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;Clear my choice

1. Break Down the Problem

The question asks which declaration is not supported by the C programming language among the given options. We need to evaluate each declaration to determine its validity in C.

2. Relevant Concepts

In C programming, certain types need to be defined correctly. The valid data types are as follows:

• int
• float
• double
• char

String types in C are usually represented as arrays of characters, not as a separate data type called String.

3. Analysis and Detail

1. String str;: This declaration is invalid because C does not have a built-in type called String. Strings are represented as arrays of characters, typically declared as char str[]; or as a pointer char *str;.

2. Both “String str;” and “float str = 3e2;”: This option implies that both declarations are invalid which is incorrect because float str = 3e2; is a valid declaration (it initializes str to 300.0).

3. float str = 3e2;: This declaration is valid. It uses scientific notation to represent 300.0.

4. char *str;: This is a valid declaration in C. It declares a pointer to a character which can be used to handle strings.

4. Verify and Summarize

The analysis shows that the only invalid declaration is String str;. The other declarations are valid according to C language standards.

Final Answer

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