ch1-reciprocal

Chapter_1

make

---

---

CONTENTS:

folder_reciprocal   (readme.txt,  folder_include,  folder_src)
folder_include   (reciprocal.hpp)
folder_src   (reciprocal.cpp,  main.c)

folder reciprocal     (readme.txt,  folder_include,  folder_src)

readme.txt     ALP, p. 19-20

Open the terminal in folder reciprocal (Ctrl+Alt+T or F4).

Compile without linking:
gcc -c -I ./include ./src/main.c
gcc -c -D NDEBUG=3 -O2 -I ./include ./src/main.c

g++ -c -I ./include ./src/reciprocal.cpp
g++ -c -D NDEBUG=3 -O2 -I ./include ./src/reciprocal.cpp

Link object files and output the executable `reciprocal':
g++ main.o reciprocal.o -o reciprocal
g++ *.o -o reciprocal

Run the program:
./reciprocal
Usage: ./reciprocal n
n - integer

./reciprocal 1
The reciprocal of 1 is 1

./reciprocal 10
The reciprocal of 10 is 0.1

./reciprocal 7
The reciprocal of 7 is 0.142857

./reciprocal 0
The reciprocal of 0 is inf

NDEBUG disables run-time errors, to focus on programming errors. See:
https://cplusplus.com/reference/cassert/assert/

Clean:
rm *.o

---

---

folder include     (reciprocal.hpp)

reciprocal.hpp     ALP, p. 19

#ifdef __cplusplus
extern "C"
{
#endif

extern double reciprocal (int i);

#ifdef __cplusplus
}
#endif

---

---

folder src     (reciprocal.cpp,  main.c)

reciprocal.cpp     ALP, p. 19

#include <cassert> // for assert()
#include "reciprocal.hpp" // for reciprocal()

double reciprocal (int i)
{
// i should be non-zero
assert (i != 0);
return 1.0 / i;
}
/*
g++ -c -I ./include ./src/reciprocal.cpp
g++ -c -D NDEBUG=3 -O2 -I ./include ./src/reciprocal.cpp
*/

---

---

main.c     ALP, p. 18-19

#include <stdio.h> // for printf(), fprintf(), stderr
#include <stdlib.h> // for atoi()
#include "reciprocal.hpp" // for reciprocal()

int main (int argc, char **argv)
{
if (argc != 2)
{
fprintf(stderr, "Usage: ./reciprocal n\n");
fprintf(stderr, "n - integer\n");
return 1; // end program, signalling error
}

int i;

i = atoi (argv[1]);
printf ("The reciprocal of %d is %g\n", i, reciprocal (i));

return 0; // end program normally
}
/*
gcc -c -I ./include ./src/main.c // compile without linking
gcc -c -D NDEBUG=3 -O2 -I ./include ./src/main.c

g++ -c -I ./include ./src/reciprocal.cpp
g++ -c -D NDEBUG=3 -O2 -I ./include ./src/reciprocal.cpp

Link object files and output the executable `reciprocal':
g++ main.o reciprocal.o -o reciprocal
g++ *.o -o reciprocal

./reciprocal
Usage: ./reciprocal n
n - integer

./reciprocal 1
The reciprocal of 1 is 1

./reciprocal 10
The reciprocal of 10 is 0.1

./reciprocal 7
The reciprocal of 7 is 0.142857

./reciprocal 0
The reciprocal of 0 is inf

rm *.o // clean
*/

---

---

Chapter_1

BACK_TO_TOP

make