added weekly exercises of isp-ws25

c/isp-ws25/weeklies/week08/w08ex02.c

@@ -0,0 +1,70 @@
+/*
+In this task, you should get familiar with
+malloc(), realloc() and free().
+
+- user input: sequence of characters
+- store in array of characters
+- dynamically increase memory on heap for array
+- temporary pointer for return value of realloc()
+- add All characters to array until Q is entered
+- check if mem-alloc OK after each malloc() / realloc()
+- If mem-alloc NOK
+  - print: "Memory allocation failed\n"
+  - return 1
+- free allocated memory at the end of main()
+
+Examples:
+
+awe  s o m e  !Q
+Entered characters: a w e s o m e !
+
+IS   P   !  :)    Q
+Entered characters: I S P ! : )
+*/
+
+#include <stdio.h>
+#include <stdlib.h> // TODO: Include the required header file
+
+int main(void)
+{
+  int capacity = 2;
+  int count = 0;
+  char *characters = NULL;
+
+  characters = (char *)calloc(capacity, sizeof(char)); // TODO: Allocate memory (make use of the variable capacity)
+  if (characters == NULL)
+  {
+    printf("Memory allocation failed\n");
+    return 1;
+  } // TODO: Check if memory could be allocated
+
+  char value = 0;
+  while (scanf(" %c", &value) && value != 'Q')
+  {
+    if (count == capacity) // TODO: Check capacitiy and use realloc() to not run out of memory on the heap
+    {
+      capacity = capacity * count;
+      char *temp_chars = (char*)realloc(characters, sizeof(char) * capacity);
+      if (temp_chars == NULL)
+      {
+        printf("Memory allocation failed\n");
+        return 1;
+      }
+      characters = temp_chars;
+    } // TODO: Check if memory could be allocated
+    characters[count] = value;
+    count++;
+    // TODO: Add the entered value to the characters array
+  }
+
+  printf("Entered characters:");
+  for (int i = 0; i < count; i++)
+  {
+    printf(" %c", characters[i]);
+  }
+  printf("\n");
+
+  free(characters); // TODO: Free the allocated memory
+
+  return 0;
+}