added weekly exercises of isp-ws25

c/isp-ws25/weeklies/week08/w08ex03.c

@@ -0,0 +1,79 @@
+/*
+This program manages a list of product prices.
+The user can enter a product price and then decide,
+whether to continue or to to stop adding new product prices.
+After adding product prices, the average price is calculated and printed.
+
+Unfortunately, there are some errors in the code.
+The compiler finds a few of them, others are logical
+errors and are not detected by the compiler.
+
+This is an example: 
+
+Price for product 1: 6.50
+Add another price? (1 = yes, 0 = no): 1
+Price for product 2: 2.80
+Add another price? (1 = yes, 0 = no): 1
+Price for product 3: 9.90
+Add another price? (1 = yes, 0 = no): 1
+Price for product 4: 450
+Add another price? (1 = yes, 0 = no): 0
+Average price: 117.30
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+
+void addPrice(float** prices, int* count, int* capacity)
+{
+  if (*count >= *capacity)
+  {
+    *capacity *= 2;
+    float *new_prices = realloc(*prices, *capacity * sizeof(float));
+    if (new_prices == NULL)
+    {
+      printf("Memory allocation failed\n");
+      return;
+    }
+    *prices = new_prices;
+  }
+
+  printf("Price for product %d: ", *count + 1);
+  scanf("%f", &(*prices)[*count]);
+}
+
+int main()
+{
+  int capacity = 2;
+  int count = 0;
+  float* prices = (float*) calloc(capacity, sizeof(float));
+  if (prices == NULL)
+  {
+    printf("Memory allocation failed\n");
+    return 1;
+  }
+
+  int additional_price = 0;
+  do
+  {
+    addPrice(&prices, &count, &capacity);
+    count++;
+    if (prices == NULL)
+    {
+      return 1;
+    }
+
+    printf("Add another price? (1 = yes, 0 = no): ");
+    scanf("%d", &additional_price);
+  } while (additional_price);
+
+  float total = 0;
+  for (int i = 0; i < count; i++)
+  {
+    total += prices[i];
+  }
+  printf("Average price: %.2f\n", total / count);
+
+  free(prices);
+  return 0;
+}