[SPCA] Restructure, intro to C continued

semester3/spca/code-examples/00_c/00_intro.c

@@ -13,4 +13,5 @@ int main( int argc, char *argv[] ) {
         printf( "Arg %d: %s\n", i, argv[ i ] ); // Outputs the i-th argument from CLI
 
     get_user_input_int( "Select a number" ); // Function calls as in any other language
+    return 0;                                // Return a POSIX exit code
 }

semester3/spca/code-examples/00_c/01_func.c

@@ -1,9 +1,11 @@
 #include "01_func.h"
+#include <stdio.h>
 
 int get_user_input_int( char prompt[] ) {
     int input_data;
-    printf( "%s", prompt );     // Always wrap strings like this for printf
-    scanf( "%d", &input_data ); // Get user input from CLI
+    printf( "%s", prompt );           // Always wrap strings like this for printf
+    scanf( "%d", &input_data );       // Get user input from CLI
+    int input_data_copy = input_data; // Value copied
 
     // If statements just like any other language
     if ( input_data )
@@ -11,6 +13,7 @@ int get_user_input_int( char prompt[] ) {
     else
         printf( "Input is zero" );
 
+    // Switch statements just like in any other language
     switch ( input_data ) {
         case 5:
             printf( "You win!" );
@@ -21,17 +24,20 @@ int get_user_input_int( char prompt[] ) {
             printf( "No win" ); // Case for any not covered input
     }
 
-    int input_data_copy = input_data;
-
     while ( input_data > 1 ) {
         input_data -= 1;
         printf( "Hello World\n" );
     }
 
+    // Inversed while loop (executes at least once)
     do {
         input_data -= 1;
         printf( "Bye World\n" );
+        if ( input_data_copy == 0 )
+            goto this_is_a_label;
     } while ( input_data_copy > 1 );
 
+this_is_a_label:
+    printf( "Jumped to label" );
     return 0;
 }

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;
+}

semester3/spca/code-examples/00_c/03_operators.c

@@ -0,0 +1,3 @@
+int main( int argc, char *argv[] ) {
+    return 0;
+}