Sample Questions on C Development

Indicate whether each of the following statements is true or false:

(1)	`_____`	#ifndef is a C function.
(2)	`_____`	#define is a preprocesor directive.
(3)	`_____`	`-pedantic-errors` is an option/switch on the `cc` command that instructs it to issue an error whenever the "base standard" requires a diagnostic.

Explain each line in the following makefile:

    test: test.o module1.o
      cc test.o module1.o -o test

    test.o: test.c module1.h
      cc -c test.c

    module1.o: module1.c module1.h
      cc -c module1.c

Assuming the following program is compiled and linked properly:

#define QUIET
#include <stdio.h>

int
main(void)
{
  printf("Execution begins...\n");

  #ifndef QUIET
  for (int i=0; i<5; i++) printf("Iteration: %d\n", i);
  #endif


  printf("Execution ends.\n");
}

what will be printed when it is executed?

cc -E -P filename

will just run the preprocessor on filename (without including linemarkers).

Given the following files:
constants.h

Rubber

library.h

#include "constants.h"
Baby Buggy

library.c

#include "constants.h"
#include "library.h"
Bumpers

what output will be generated by:

    cc -E -P library.c

Now, suppose the files are as follows:
constants.h

#ifndef CONSTANTS_H
#define CONSTANTS_H
Rubber
#endif

library.h

#ifndef LIBRARY_H
#define LIBRARY_H
#include "constants.h"
Baby Buggy
#endif

library.c

#include "constants.h"
#include "library.h"
#define  BUMPERS Bumpers
BUMPERS

what output will be generated by:

    cc -E -P library.c

Suppose the following code is in a file named calculator.c and that there is no file named calculator.h.
```
int
add (int a, int b)
{
  return a+b;
}
```
1. Will the command cc -c calculator.c -o calculator.o execute without error? If not, why not (and will the error be generated by the preprocessor, compiler, or linker)? If so, what file will be produced?
2. Will the command cc calculator.c execute without error? If not, why not (and will the error be generated by the preprocessor, compiler, or linker)? If so, what file will be produced?
Suppose the following code is in a file named calculator.c and that there is no file named calculator.h.
```
int
bump(int a)
{
  return a + increase;
}
```
1. Will the command cc -c calculator.c -o calculator.o execute without error? If not, why not (and will the error be generated by the preprocessor, compiler, or linker)? If so, what file will be produced?
2. Suppose the following is added to the top of the file.
```
#include "calculator.h"
```
  Will the command cc -c calculator.c -o calculator.o execute without error? If not, why not (and will the error be generated by the preprocessor, compiler, or linker)? If so, what file will be produced?
Suppose we have the following files.
calculator.h
```
int increase;
```
calculator.c
```
#include "calculator.h"

int
bump(int a)
{
  return a + increase;
}
```
gradebook.c
```
#include "calculator.h"
#include <stdio.h>

int main(void)
{
  increase = 10;
  printf("Midterms Average: %d\n", add(80, 100) / 2);
  printf("Final (Curved):   %d\n", bump(70));

  return 0;
}
```
1. Will the command cc -c calculator.c -o calculator.o execute without error? If not, why not (and will the error be generated by the preprocessor, compiler, or linker)? If so, what file will be produced?
2. Will the command cc -pedantic -pedantic-errors -Wall -c gradebook.c -o gradebook.o execute without error? If not, why not (and will the error be generated by the preprocessor, compiler, or linker)? If so, what file will be produced?
3. Will the command cc -Wall -c gradebook.c -o gradebook.o execute without error? If not, why not (and will the error be generated by the preprocessor, compiler, or linker)? If so, what file will be produced?
4. Will the command cc gradebook.o calculator.o -o gradebook execute without error? If not, why not (and will the error be generated by the preprocessor, compiler, or linker)? If so, what file will be produced?
5. Suppose the file calculator.h is changed so that it contains the line extern int increase;. Will the two .c files compile? Will they link? If not, why not?
Given the following files: lib.h
```
#ifndef LIB_H
#define LIB_H

int 
net_price(int price, int discount);

static int 
validate(int n);

#endif
```
lib.c
```
#include "lib.h"

int 
net_price(int price, int discount)
{
  return validate(price - discount);
}

static int 
validate(int n)
{
  if (n < 0) return 0;
  else       return n;
}
```
pricer.c
```
#include "lib.h"

int 
main(void)
{
  int i, j;

  i = validate(-5);
  j = net_price(6, 2);
}
```
1. Will the command cc -pedantic -pedantic-errors -Wall -c lib.c -o lib.o execute without error? If not, why not (and will the error be generated by the preprocessor, compiler, or linker)? If so, what file will be produced?
2. Will the command cc -pedantic -pedantic-errors -Wall -c pricer.c -o pricer.o execute without error? If not, why not (and will the error be generated by the preprocessor, compiler, or linker)? If so, what file will be produced?
3. Will the command cc -Wall -c pricer.c -o pricer.o execute without error? If not, why not (and will the error be generated by the preprocessor, compiler, or linker)? If so, what file will be produced?
4. Will the command cc pricer.o lib.o -o pricer execute without error? If not, why not (and will the error be generated by the preprocessor, compiler, or linker)? If so, what file will be produced?