more examples

c_pointers/chapter_5.c

@@ -3,6 +3,22 @@
 #include <string.h>
 
 
+// summary ofstring placement
+/*
+char *globalHeader = "Chapter";
+char globalArrayHeader[] = "Chapter";
+
+void displayHeader() {
+    static char *staticHeader = "Chapter";
+    char *localHeader = "Chapter";
+    static char staticArrayHeader[] = "Chapter";
+    char localArrayHeader[] = "Chapter";
+    char *heapHeader = malloc(strlen("Chapter")+1);
+    strcpy(heapHeader, "Chapter");
+}
+*/
+
+
 int main(void) {
 
     // print size of char & character literal
@@ -51,6 +67,56 @@ int main(void) {
         }
         printf("\n");
 
+        // direct init with character pointer
+        // don't create a new copy, instead a reference to string literal pool only
+        char *headerRef = "Media Player";
+        printf("%s\n", headerRef);
+
+        // you shouldn't assign a char pointer with a character literal
+        // because character literals is of type int
+        // wrong:
+        // char *prefix = '+';
+        // better:
+        char *prefix = malloc(2);
+        *prefix = '+';
+        *(prefix + 1) = 0;
+        printf("%s\n", prefix);
+        free(prefix);
+
+        // string initialisation from standard in
+        // don't forget to allocate memory before read from standard in
+        // wrong:
+        // char *command;
+        // printf("%s: ", "Enter a command");
+        // scanf("%s", command);
+        // better:
+        char *command = malloc(11);
+        printf("%s: ", "Enter a command");
+        scanf("%10s", command);
+        printf("You entered: %s with length: %zu\n", command, strlen(command));
+        free(command);
+
+        // memset buffer overflow test
+        // executes without warnings or errors on osx :D
+        char *mem = malloc(11);
+        memset(mem, 0x42, 64);
+        free(mem);
+
+    }
+
+    // standard string operations
+
+    // comparing strings
+    {
+        char command[16];
+        printf("Enter a command: ");
+        scanf("%15s", command);
+        // return value of strlen == 0 -> strings are equal
+        if (!strcmp(command, "quit")) {
+            printf("The command was quit\n");
+        } else {
+            printf("The command wasn't quit\n");
+        }
     }
 
     return 0;