$question
$answer` if `question.content[]` is `Markdown.Paragraph`
# This will print the question on a new line and we don't want that:
h = HTML(_inline_html(question.content[]))
return qa(h, answer)
end
endmetadatashow_logsèdisabled®skip_as_script«code_folded$4072072d-c543-43bf-87ad-1f201bd21c59cell_id$4072072d-c543-43bf-87ad-1f201bd21c59codehc"""struct vector_t {
int length; // nombre d'élements
float *tab; // tableau avec les réels
};"""metadatashow_logsèdisabled®skip_as_script«code_folded$488d8bed-855f-470a-a2fa-68c13fd08739cell_id$488d8bed-855f-470a-a2fa-68c13fd08739code qa(c"struct vector_t * init(int size, float val) {", c"""
// manque tests erreur malloc
struct vector_t *t = (struct vector_t *)malloc(sizeof(struct vector_t));
t->v = (float *)malloc(size * sizeof(float));
t->size = size;
for (int i = 0; i < size; i++)
{
*(t->v + i) = val;
}
""")metadatashow_logsèdisabled®skip_as_script«code_folded$b8392f14-05d4-43e4-bd2a-3d4ba6ced65bcell_id$b8392f14-05d4-43e4-bd2a-3d4ba6ced65bcodeZmd"Laquelle de ces deux fonctions présente une façon correcte de retourner un tableau ?"metadatashow_logsèdisabled®skip_as_script«code_folded$1f190c17-4feb-41b2-a10a-60fb191d250ecell_id$1f190c17-4feb-41b2-a10a-60fb191d250ecodeMwrap_compile_and_run(c"""
float A[2][2] = {{1, 0}, {2, 3}};
A[1][1] = 4;
""")metadatashow_logsèdisabled®skip_as_script«code_folded$406d30a9-f477-4898-9caf-770fcc25b2a9cell_id$406d30a9-f477-4898-9caf-770fcc25b2a9codeFmd"Comment libérer la mémoire quand le vecteur est devenu inutile ?"metadatashow_logsèdisabled®skip_as_script«code_folded$accfaade-96ce-4869-83ce-9dd5489b65a2cell_id$accfaade-96ce-4869-83ce-9dd5489b65a2codetutor(c"""
#include The End
""")
url = "https://app.wooclap.com/$link"
a = HTML("""$url""")
qr = img("https://api.qrserver.com/v1/create-qr-code/?size=150x150&data=$url", :height => 50, name = "$link.png")
return three_columns(logo, a, qr)
endmetadatashow_logsèdisabled®skip_as_script«code_folded$1a82ab2b-dd7c-4b48-b263-e71b13ba0fb2cell_id$1a82ab2b-dd7c-4b48-b263-e71b13ba0fb2codemd"""
Si la matrice a été créée par
```c
float **matrice = (float **)malloc(2 * sizeof(float *));
float *ligne0 = (float *)malloc(2 * sizeof(float));
float *ligne1 = (float *)malloc(2 * sizeof(float));
matrice[0] = ligne0;
matrice[1] = ligne1;
```
"""metadatashow_logsèdisabled®skip_as_script«code_folded$acfa3f43-215e-4c97-bf2a-0069e78f95b4cell_id$acfa3f43-215e-4c97-bf2a-0069e78f95b4codemd"## Matrices en C"metadatashow_logsèdisabled®skip_as_script«code_folded$319bc8b4-7139-43b0-a57b-66c6a9da7cb9cell_id$319bc8b4-7139-43b0-a57b-66c6a9da7cb9code,md"# Structure différente du stack et heap"metadatashow_logsèdisabled®skip_as_script«code_folded$47279972-433b-46be-b511-170698ff8753cell_id$47279972-433b-46be-b511-170698ff8753code*md"""
Comment construire une matrice ?
"""metadatashow_logsèdisabled®skip_as_script«code_folded$0e0ddf7c-a34b-447a-8142-334d14f96ae1cell_id$0e0ddf7c-a34b-447a-8142-334d14f96ae1code md"## Allocation de la mémoire"metadatashow_logsèdisabled®skip_as_script«code_folded$38e67b29-707f-4718-b9cc-2a1a62f32143cell_id$38e67b29-707f-4718-b9cc-2a1a62f32143codewooclap("JAPRXX")metadatashow_logsèdisabled®skip_as_script«code_folded$0b41747b-fe00-49a0-9ed9-99f0b2046b2ecell_id$0b41747b-fe00-49a0-9ed9-99f0b2046b2ecodec"""
float **matrice = (float **)malloc(2 * sizeof(float *));
float *ligne0 = (float *)malloc(2 * sizeof(float));
float *ligne1 = (float *)malloc(2 * sizeof(float));
matrice[0] = ligne0;
matrice[1] = ligne1;
matrice[0][0] = 1; // 1
*(matrice[0]) = 1; // 2
*(matrice) = 1; // 3
"""metadatashow_logsèdisabled®skip_as_script«code_folded$67cf8ac0-5b91-4d19-aca4-4309f3109a0ccell_id$67cf8ac0-5b91-4d19-aca4-4309f3109a0ccode(md"## Comment faire matrice[1][0] = 2 ?"metadatashow_logsèdisabled®skip_as_script«code_folded$87877209-958b-4635-bdbc-97548acdfb3fcell_id$87877209-958b-4635-bdbc-97548acdfb3fcodexmd"""
Toutes les fonctions doivent vérifier leurs arguments et retourner
* -1 en cas d'erreur
* 0 en cas de succès
"""metadatashow_logsèdisabled®skip_as_script«code_folded$9160427d-4db7-4a97-9dde-14d19d59b1efcell_id$9160427d-4db7-4a97-9dde-14d19d59b1efcode'c"""
float **matrice = (float **)malloc(2 * sizeof(float *));
float *ligne0 = (float *)malloc(2 * sizeof(float));
float *ligne1 = (float *)malloc(2 * sizeof(float));
matrice[0] = ligne0;
matrice[1] = ligne1;
*(*(++matrice)) = 2; // 1
*(*(matrice + 1)) = 2; // 2
*(*matrice + 1) = 2; // 3
"""metadatashow_logsèdisabled®skip_as_script«code_folded$14a56b43-789a-42f0-9228-0c6a660629c9cell_id$14a56b43-789a-42f0-9228-0c6a660629c9codeDmd"`mapreduce` donne un exemple de fonction d'ordre supérieur en C"metadatashow_logsèdisabled®skip_as_script«code_folded$90a4fe3c-02c7-46e6-b2fb-526e73508101cell_id$90a4fe3c-02c7-46e6-b2fb-526e73508101codeOusing PlutoUI, PlutoUI.ExperimentalLayout, PlutoTeachingTools, HypertextLiteralmetadatashow_logsèdisabled®skip_as_script«code_folded$49f0db66-da21-42b0-91d5-db04075e559acell_id$49f0db66-da21-42b0-91d5-db04075e559acode#section("Un vecteur \"Java\" en C")metadatashow_logsèdisabled®skip_as_script«code_folded$cb9c27b9-ce7d-4bdf-af7d-c88883a210bccell_id$cb9c27b9-ce7d-4bdf-af7d-c88883a210bccode_c"""
/*
* libère la mémoire utilisée pour le vecteur
* -1 en cas d'erreur, 0 sinon
*/
"""metadatashow_logsèdisabled®skip_as_script«code_folded$3b5e218f-c134-40a9-9bc3-1fbab8d64d62cell_id$3b5e218f-c134-40a9-9bc3-1fbab8d64d62code
O. Bonaventure, B. Legat, M. Baerts
$(PlutoTeachingTools.ChooseDisplayMode()) $(PlutoUI.TableOfContents(depth=1)) """)metadatashow_logsèdisabled®skip_as_script«code_folded$b58ba8eb-0661-4eac-8ead-2daff4126d57cell_id$b58ba8eb-0661-4eac-8ead-2daff4126d57codec""" } return 0; } """metadatashow_logsèdisabled®skip_as_script«code_folded$c132bea8-1ffe-4015-aaa7-66a67a806f48cell_id$c132bea8-1ffe-4015-aaa7-66a67a806f48codebegin abstract type Code end struct CCode <: Code code::String end macro c_str(s) return :($CCode($(esc(s)))) end struct CppCode <: Code code::String end macro cpp_str(s) return :($CppCode($(esc(s)))) end struct CLCode <: Code code::String end macro cl_str(s) return :($CLCode($(esc(s)))) end struct JavaCode <: Code code::String end macro java_str(s) return :($JavaCode($(esc(s)))) end source_extension(::CCode) = "c" source_extension(::CppCode) = "cpp" source_extension(::CLCode) = "cl" source_extension(::JavaCode) = "java" compiler(::CCode, mpi::Bool) = mpi ? "mpicc" : "clang" function compiler(::CppCode, mpi::Bool) @assert !mpi return "clang++" end inline_code(code::AbstractString, ext::String) = HTML("""$code""")
inline_code(code::Code) = inline_code(code.code, source_extension(code))
function md_code(code::AbstractString, ext::String)
code = "```" * ext * '\n' * code
if code[end] != '\n'
code *= '\n'
end
return Markdown.parse(code * "```")
end
md_code(code::Code) = md_code(code.code, source_extension(code))
function Base.show(io::IO, m::MIME"text/html", code::Code)
return show(io, m, md_code(code))
end
function compile(
code::Code;
lib,
emit_llvm = false,
cflags = ["-O3"],
mpi::Bool = false,
use_system::Bool = mpi || "-fopenmp" in cflags, # `-fopenmp` will not work with pure Clang_jll, it needs openmp installed as well
verbose = 0,
)
path = mktempdir()
main_file = joinpath(path, "main." * source_extension(code))
bin_file = joinpath(path, ifelse(emit_llvm, "main.llvm", ifelse(lib, "lib.so", "bin")))
write(main_file, code.code)
args = String[]
if !use_system && code isa CppCode
# `clang++` is not part of `Clang_jll`
push!(args, "-x")
push!(args, "c++")
end
append!(args, cflags)
if lib
push!(args, "-fPIC")
push!(args, "-shared")
end
if emit_llvm
push!(args, "-S")
push!(args, "-emit-llvm")
end
push!(args, main_file)
push!(args, "-o")
push!(args, bin_file)
try
if use_system
cmd = Cmd([compiler(code, mpi); args])
if verbose >= 1
@info("Compiling : $cmd")
end
run(cmd)
else
Clang_jll.clang() do exe
cmd = Cmd([exe; args])
if verbose >= 1
@info("Compiling : $cmd")
end
run(cmd)
end
end
catch err
if err isa ProcessFailedException
return
else
rethrow(err)
end
end
return bin_file
end
function emit_llvm(code; kws...)
llvm = compile(code; lib = false, emit_llvm = true, kws...)
InteractiveUtils.print_llvm(stdout, read(llvm, String))
return code
end
function compile_lib(code::Code; kws...)
return codesnippet(code), compile(code; lib = true, kws...)
end
function compile_and_run(code::Code; verbose = 0, args = String[], valgrind::Bool = false, mpi::Bool = false, num_processes = nothing, show_run_command = !isempty(args) || verbose >= 1, kws...)
bin_file = compile(code; lib = false, mpi, verbose, kws...)
if !isnothing(bin_file)
cmd_vec = [bin_file; args]
if valgrind
cmd_vec = ["valgrind"; cmd_vec]
end
if mpi
if !isnothing(num_processes)
cmd_vec = [["-n", string(num_processes)]; cmd_vec]
end
cmd_vec = ["mpiexec"; cmd_vec]
end
cmd = Cmd(cmd_vec)
if show_run_command
@info("Running : $cmd") # `2:end-1` to remove the backsticks
end
try
run(cmd)
catch err
@warn(string(typeof(err)))
end
end
return codesnippet(code)
end
function wrap_in_main(content)
code = content.code
if code[end] == '\n'
code = code[1:end-1]
end
return typeof(content)("""
#include void destroy(struct vector_t *vect) {
void destroy(struct vector_t *vect) { free(vect->v);
free(vect);
}Heap ou stack ?
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text/htmlpersist_js_state¤mime'application/vnd.pluto.divelement+objectlast_run_timestampAڝ,ythas_pluto_hook_features¬rootassigneecell_id$9cb862ff-275e-4f1d-8104-c1b8350725dadepends_on_disabled_cells§runtime published_object_keysdepends_on_skipped_cells§errored$d107cd6f-c45c-4289-bd0f-5f329633fddaqueued¤logsrunning¦outputbody&tutor (generic function with 1 method)persist_js_state¤mimetext/plainlast_run_timestampAڝ2has_pluto_hook_features¬rootassigneecell_id$d107cd6f-c45c-4289-bd0f-5f329633fddadepends_on_disabled_cells§runtime /(published_object_keysdepends_on_skipped_cells§errored$378c90d9-e206-4858-b362-4015ca46bbb0queued¤logsrunning¦outputbody(section (generic function with 1 method)persist_js_state¤mimetext/plainlast_run_timestampAڝJ{has_pluto_hook_features¬rootassigneecell_id$378c90d9-e206-4858-b362-4015ca46bbb0depends_on_disabled_cells§runtime1_published_object_keysdepends_on_skipped_cells§errored$44c8617f-ba56-40fe-80b4-963cf6e6f4b5queued¤logsrunning¦outputbodyjModification d'un élément
Comment implémenter set ?
if (i < 0 || i >= v->length)
return -1;
*(v->tab + i) = val;
return 0;
}Comment implémenter get ?
if (i < 0 || i >= v->length)
return -1;
*val = *(v->tab + i);
return 0;
}Libération de la mémoire
persist_js_state¤mimetext/htmllast_run_timestampAڝRxhas_pluto_hook_features¬rootassigneecell_id$03847d85-c675-4b4a-9331-fd7a32b26938depends_on_disabled_cells§runtime 6?published_object_keysdepends_on_skipped_cells§errored$27b6779a-5624-4e8e-ae32-8a8971923d01queued¤logsrunning¦outputbodyoint *stack()
{
int v[] = {1, 2, 3};
return v;
}
int *heap()
{
int *v = (int *)malloc(3 * sizeof(int));
v[0] = 1;
v[1] = 2;
v[2] = 3;
return v;
}Première approche, un malloc par ligne
#include <stdio.h>
int main(int argc, char **argv)
{
for (int i = 0; i < argc; i++)
{
printf("arg[%d]: %s\n", i, argv[i]);
}
}float *matrice1 = (float *)malloc(4 * sizeof(float));
matrice1[1][1] = 4;struct vector_t {
int length; // nombre d'élements
float *tab; // tableau avec les réels
};struct vector_t * init(int size, float val) {
struct vector_t * init(int size, float val) {// manque tests erreur malloc
struct vector_t *t = (struct vector_t *)malloc(sizeof(struct vector_t));
t->v = (float *)malloc(size * sizeof(float));
t->size = size;
for (int i = 0; i < size; i++)
{
*(t->v + i) = val;
}Laquelle de ces deux fonctions présente une façon correcte de retourner un tableau ?
float A[2][2] = {{1, 0}, {2, 3}};
A[1][1] = 4;Comment libérer la mémoire quand le vecteur est devenu inutile ?
text/htmlclassnamestyleflex-grow: 1;children text/html'application/vnd.pluto.divelement+objectohttps://app.wooclap.com/JAPRXXtext/htmlclassnamestyleflex-grow: 1;children text/html'application/vnd.pluto.divelement+objecttext/htmlpersist_js_state¤mime'application/vnd.pluto.divelement+objectlast_run_timestampAڝ+`has_pluto_hook_features¬rootassigneecell_id$6531f0d6-cf62-46ca-8dd2-befda43806d7depends_on_disabled_cells§runtime K published_object_keysdepends_on_skipped_cells§errored$e0bfde10-5b3d-48b2-aa03-a1e6b0fc97e3queued¤logsrunning¦outputbodyYThe End
persist_js_state¤mimetext/htmllast_run_timestampAڝShhas_pluto_hook_features¬rootassigneecell_id$e0bfde10-5b3d-48b2-aa03-a1e6b0fc97e3depends_on_disabled_cells§runtime qpublished_object_keysdepends_on_skipped_cells§errored$4e5e1340-c2e6-4b4a-bfb9-e1096d179040queued¤logsrunning¦outputbodyTRetourner un tableau
struct vector_t {
int length; // nombre d'élements
float *tab; // tableau avec les réels
};Récupération d'un élément
int init(int size, float val, struct vector_t **v)
{
if ((size < 0) || v == NULL)
return -1;
*v = (struct vector_t *)malloc(sizeof(struct vector_t));
if (*v == NULL)
{
return -1;
}
(*v)->tab = (float *)malloc(size * sizeof(float));
if ((*v)->tab == NULL)
{
return -1;
}
(*v)->length = size;
for (int i = 0; i < size; i++)
{Libération de la mémoire
Visualization de init
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float get(struct vector_t *t, int i) { return *(t->v + i);
}Une autre implémentation …
Initialisation d'une valeur
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struct vector_t
{
int size;
float *v;
};Comment mettre une matrice 2x2 sur le heap ?
Visualisation
Comment libérer la mémoire avec free ?
free(ligne0);
free(ligne1);
free(matrice);int destroy(struct vector_t *v) {
int destroy(struct vector_t *v) { free(v->tab);
free(v);
return 0;
}L'importance de l'ordre de désallocation
void set(struct vector_t *t, int i, float val) {
void set(struct vector_t *t, int i, float val) { if ((i < t->size) && (i > 0))
*(t->v+i)=val;
}float **matrice = (float **)malloc(2 * sizeof(float *));
float *ligne0 = (float *)malloc(2 * sizeof(float));
float *ligne1 = (float *)malloc(2 * sizeof(float));
matrice[0] = ligne0;
matrice[1] = ligne1;
*(*matrice + 1) = 0; // 1
*(matrice++) = 0; // 2
*(matrice[0] + 1) = 0; // 3/*
* @pre
* @post retourne le ième élément du tableau dans val
* -1 en cas d'erreur, 0 sinon
*/
int get(struct vector_t *v, int i,
float val // 1
float **val // 2
float *val // 3
) {int argc: Le nombre d'arguments (incluant le nom de l'exécutable)char **argv: liste des arguments initialisée par le système d’exploitation au lancement du programme
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Si la matrice a été créée par
float **matrice = (float **)malloc(2 * sizeof(float *));
float *ligne0 = (float *)malloc(2 * sizeof(float));
float *ligne1 = (float *)malloc(2 * sizeof(float));
matrice[0] = ligne0;
matrice[1] = ligne1;Matrices en C
Structure différente du stack et heap
Comment construire une matrice ?
Allocation de la mémoire
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float *ligne0 = (float *)malloc(2 * sizeof(float));
float *ligne1 = (float *)malloc(2 * sizeof(float));
matrice[0] = ligne0;
matrice[1] = ligne1;
matrice[0][0] = 1; // 1
*(matrice[0]) = 1; // 2
*(matrice) = 1; // 3Comment faire matrice[1][0] = 2 ?
Toutes les fonctions doivent vérifier leurs arguments et retourner
-1 en cas d'erreur
0 en cas de succès
float **matrice = (float **)malloc(2 * sizeof(float *));
float *ligne0 = (float *)malloc(2 * sizeof(float));
float *ligne1 = (float *)malloc(2 * sizeof(float));
matrice[0] = ligne0;
matrice[1] = ligne1;
*(*(++matrice)) = 2; // 1
*(*(matrice + 1)) = 2; // 2
*(*matrice + 1) = 2; // 3mapreduce donne un exemple de fonction d'ordre supérieur en C
Un vecteur "Java" en C
/*
* libère la mémoire utilisée pour le vecteur
* -1 en cas d'erreur, 0 sinon
*/Deuxième approche, un malloc pour toutes les valeurs
Toujours free dans le sens inverse de malloc
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Pointeur de fonction
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Arguments de main
LEPL1503/LSINC1503 - Cours 2
O. Bonaventure, B. Legat, M. Baerts
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return 0;
}Initialisation
/*
* @pre
* @post place val comme ième élément
* du tableau
* -1 en cas d'erreur, 0 sinon
*/
int set(struct vector_t *v, int i,
float val // 1
float **val // 2
float *val // 3
) {Stack : Pile de mémoire locale des functions, structure connue à la compilation
Heap : Alloué et désalloué avec des tailles connues à l'exécution. L'OS fait de son mieux pour organiser cette mémoire et réassigner les fragments formés suite aux désallocations
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Quels arguments ?
Première implémentation
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int length; // nombre d'élements
float *tab; // tableau avec les réels
};struct vector_t {
int length; // nombre d'élements
float *tab; // tableau avec les réels
};Comment assigner la valeur val au iième élément ?
float *t = (*v)->tab;
t[i] = val;ou
*((*v)->tab + i) = val;/*
* @pre
* alloue la mémoire pour un vecteur de size éléments
* initialisés à la valeur val
* @return -1 si erreur, 0 sinon
*/
int init(int size, float val,
struct vector_t v, // 1
struct vector_t **v, // 2
struct vector_t *v, // 3
)Une telle matrice sera stockée sur le stack (variable locale) ou dans la zone données (variable globale)