From 1a4c5748e883bcffcfb9e2ee2866d6492dde4093 Mon Sep 17 00:00:00 2001
From: Bappoz <landradezanetti@gmail.com>
Date: Wed, 24 Jun 2026 02:02:21 -0300
Subject: [PATCH] =?UTF-8?q?feat(examples):=20adicionar=20programa-demo=20p?=
 =?UTF-8?q?ara=20a=20apresenta=C3=A7=C3=A3o=20final?=
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Adiciona src/examples/demo_presentation.c com um programa curto que
combina variaveis/expressoes, funcao recursiva (factorial) e controle
de fluxo (if/while), dentro do subconjunto estavel do backend atual
(sem struct/ponteiro/switch, ainda nao suportados no codegen).

Documenta a saida esperada (exit code 80) no cabecalho do arquivo e
adiciona um smoke test (smoke_presentation_demo_runs) que compila e
executa o exemplo de ponta a ponta via gcc, garantindo que ele
continue funcionando com o pipeline atual.

Resolve #163
---
 src/examples/demo_presentation.c | 39 ++++++++++++++++++++++++++++++++
 tests/exe_smoke_test.rs          | 17 ++++++++++++++
 2 files changed, 56 insertions(+)
 create mode 100644 src/examples/demo_presentation.c

diff --git a/src/examples/demo_presentation.c b/src/examples/demo_presentation.c
new file mode 100644
index 0000000..540f172
--- /dev/null
+++ b/src/examples/demo_presentation.c
@@ -0,0 +1,39 @@
+/*
+ * Programa-demo para a apresentação final (issue #163).
+ *
+ * Mostra, em poucas linhas, os recursos centrais já estáveis do
+ * subconjunto de C suportado pelo compilador:
+ *   - variaveis e expressoes aritmeticas
+ *   - funcoes com chamada recursiva (factorial)
+ *   - controle de fluxo: if/else e while
+ *
+ * Saida esperada: exit code 80
+ *   factorial(4)          = 24
+ *   sum_even_squares(6)   = 2*2 + 4*4 + 6*6 = 56
+ *   24 + 56               = 80
+ */
+
+int factorial(int n) {
+    if (n <= 1) {
+        return 1;
+    }
+    return n * factorial(n - 1);
+}
+
+int sum_even_squares(int n) {
+    int total = 0;
+    int i = 1;
+    while (i <= n) {
+        if (i % 2 == 0) {
+            total = total + i * i;
+        }
+        i = i + 1;
+    }
+    return total;
+}
+
+int main(void) {
+    int fact4 = factorial(4);
+    int squares = sum_even_squares(6);
+    return fact4 + squares;
+}
diff --git a/tests/exe_smoke_test.rs b/tests/exe_smoke_test.rs
index 63d4f45..9bbaf5d 100644
--- a/tests/exe_smoke_test.rs
+++ b/tests/exe_smoke_test.rs
@@ -141,3 +141,20 @@ fn smoke_function_call_runs() {
     #[cfg(unix)]
     assert_eq!(status.code(), Some(42));
 }
+
+/// Garante que o programa-demo da apresentação final (issue #163), em
+/// `src/examples/demo_presentation.c`, continua compilando e produzindo o
+/// exit code documentado no cabeçalho do arquivo.
+#[test]
+fn smoke_presentation_demo_runs() {
+    require_gcc!();
+
+    let path = PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("src/examples/demo_presentation.c");
+    let source = std::fs::read_to_string(&path)
+        .unwrap_or_else(|e| panic!("falha ao ler '{}': {e}", path.display()));
+
+    let status = compile_and_run("presentation_demo", &source);
+
+    #[cfg(unix)]
+    assert_eq!(status.code(), Some(80));
+}