scope example explained with a and b variables global and local

c-basic/scope.c

@@ -0,0 +1,53 @@
+/**
+
+scope.c - scope and variables explained
+   
+Copyright (C) 2023-2024 Mert Gör and contributors
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+Feel free to send an email to mertgor@masscollabs.xyz for your questions
+
+ **/
+
+#include <stdio.h>
+
+int main() {
+  int a;
+  {
+    int b;
+    b = 20;
+    a = 10;
+    printf("a : %d, b : %d\n", a, b); // correct way to get done the job/task
+  }
+  printf("a : %d\n", a); // correct way to get done the job/task for a variable
+  // printf("b : %d\n", b); // error !
+  /**
+     ~/Projects/hwpplayer1/c-course/c-basic $ gcc scope.c 
+scope.c: In function ‘main’:
+scope.c:35:22: error: ‘b’ undeclared (first use in this function)
+   35 |   printf("b : %d\n", b); // error !
+      |                      ^
+scope.c:35:22: note: each undeclared identifier is reported only once for each function it appears in
+   **/
+
+  return 0;
+  
+}
+
+/**
+   ~/Projects/hwpplayer1/c-course/c-basic $ ./a.out 
+a : 10, b : 20
+a : 10
+ **/