[SPCA] Restructure, intro to C continued

semester3/spca/code-examples/00_c/02_declarations.c

@@ -0,0 +1,32 @@
+int my_int;              // Allocates memory on the stack.
+                         // Variable is global (read / writable by entire program)
+static int my_local_int; // only available locally (in this file)
+const int MY_CONST = 10; // constant (immutable), convention: SCREAM_CASE
+
+enum { ONE, TWO } num; // Enum. ONE will get value 0, TWO has value 1
+
+enum { O = 2, T = 1 } n; // Enum with values specified
+
+// Structs are like classes, but contain no logic
+struct MyStruct {
+        int el1;
+        int el2;
+};
+
+int fun( int j ) {
+    static int i = 0;              // Persists across calls of fun
+    short my_var = 1;              // Block scoped (deallocated when going out of scope)
+    int my_var_dbl = (int) my_var; // Explicit casting (works between almost all types)
+    return i;
+}
+
+int main( int argc, char *argv[] ) {
+    if ( ( my_local_int = fun( 10 ) ) ) {
+        // Every c statement is also an expression, i.e. you can do the above!
+    }
+    struct MyStruct test;            // Allocate memory on stack for struct
+    struct MyStruct *test_p = &test; // Pointer to memory where test resides
+    test.el1 = 1;                    // Direct element access
+    test_p->el2 = 2;                 // Via pointer
+    return 0;
+}