eight questions about programming C, thank you

1: What is wrong with the following program? You may assume that additional files (not shown) are present.

#include  

#include  

int main(void) { 

 int x; 

 scanf("%d", &x); 

 do_calculation(x); 

 return 0; 

} 

A. Nothing is wrong.

B. There is a problem with the scanf line.

C. There is no function prototype for the function "do_calculation".

D. Something else.

2: What is the point of having header guards?

A. They protect the header from corruption.

B. They ensure that a header file can only be compiled if the source file is included.

C. They stop a header file from being included multiple times.

D. They are the shields that guards the realms of men.

3: Which of the following need to be compiled?

Source Files

B. Header Files

C. Documentation Files

D. All Files

4: Which of the following can NOT be put in source files?

A. Include Directives

B. Macro Definitions

C. Function Definitions

D. External Variables

E. All of the above CAN be put in source files.

5: Which header files should be included in a source file?

A. The headers with function declarations the source file is using.

B. All headers in the project.

C. Headers that are related to the source files topic.

D. None of the above.

6: Are makefiles necessary for the compilation of multi-source file programs?

Yes

No

7: If you invoke the make utility without a target (i.e. "make"), which target will be built?

A. The last target

B. The first target

C. All the targets

D. None of the targets

8: When do you need to use the "extern" keyword?

A. When initializing an external variable.

B. When sharing an external variable.

C. When an external variable is used.

D. Never, it is optional.