🎉

Author: pl3onasm

Extra-C/prob03/prob3-2.c

@@ -5,9 +5,8 @@
   version: 3.2, using clib library 
     also changed the implementation to use only two
     rows of size n instead of a 2D array of size n²
-    Time complexity is still O(n²)
-    Space complexity is now O(n) instead of O(n²) of
-    the previous implementation
+    Time complexity is still O(n²), but the space 
+    complexity is now O(n) instead of O(n²) 
 */
 
 #include <stdio.h>
@@ -16,15 +15,15 @@
 
 int maxPath (int *row1, int *row2, int n) {
   /* computes the maximum path cost */
+  
   // read the first row
   READ_ARRAY(row1, "%d ", 1);
 
-  // calculate the maximum path cost for each cell
   for (int i = 2; i <= n; ++i) {
     // read the next row
     READ_ARRAY(row2, "%d ", i);
 
-    // calculate the maximum path cost for each cell
+    // compute the maximum path cost for each cell
     for (int j = 0; j < i; ++j) {
       if (j == 0)
         row2[j] += row1[j];

Functions/clib/clib.h

@@ -1,6 +1,14 @@
 /* file: clib.h
    author: David De Potter
    description: header file for the clib library
+   NOTES:
+   - I mostly use ints just to be in line with the course material. 
+   - I have not wrapped any macros in do { ... } while(0) loops, 
+     because I don't see the need for it.
+   - Always use a unique name for the array or matrix when using 
+     the create and read macros, as the macro creates a variable 
+     with that name. No need to declare the variable before using
+     the macro.
 */
 
 #ifndef CLIB_H_INCLUDED    
@@ -13,8 +21,6 @@
 
 #define MIN(a, b) ((a) < (b) ? (a) : (b))
 
-#define ABS(a) ((a) < 0 ? -(a) : (a))
-
 #define SIGN(a) ((a) > 0 ? 1 : ((a) < 0 ? -1 : 0))
 
   // macro definition for swapping two variables
@@ -24,20 +30,20 @@
   // Examples:  PRINT_ARRAY(myInts, "%d", 10);
   //            PRINT_ARRAY(myDbls, "%.2lf", 20);
 #define PRINT_ARRAY(arr, format, len) \
-  for (int arr##i = 0; arr##i < len; ++arr##i){ \
-    printf(format, arr[arr##i]);\
-    printf(arr##i == len-1 ? "\n" : ", "); \
+  for (int i = 0; i < len; ++i){ \
+    printf(format, arr[i]);\
+    printf(i == len-1 ? "\n" : ", "); \
   } 
 
   // macro for printing a matrix of a given type and dimensions
   // Examples:  PRINT_MATRIX(myInts, "%d", rows, cols);
   //            PRINT_MATRIX(myDbls, "%.2lf", rows, cols);
   //            PRINT_MATRIX(myChrs, "%c", rows, cols);
 #define PRINT_MATRIX(matrix, format, rows, cols) \
-  for (int matrix##i = 0; matrix##i < rows; ++matrix##i) { \
-    for (int matrix##j = 0; matrix##j < cols; ++matrix##j) {\
-      printf(format, matrix[matrix##i][matrix##j]); \
-      printf(matrix##j == cols-1 ? "\n" : " "); \
+  for (int i = 0; i < rows; ++i) { \
+    for (int j = 0; j < cols; ++j) {\
+      printf(format, matrix[i][j]); \
+      printf(j == cols-1 ? "\n" : " "); \
     } \
   } 
 
@@ -54,31 +60,31 @@
   //            CREATE_MATRIX(myChrs, char, 15, 10);
 #define CREATE_MATRIX(type, matrix, rows, cols) \
   type **matrix = safeCalloc(rows, sizeof(type *)); \
-  for (int matrix##i = 0; matrix##i < rows; ++matrix##i) \
-    matrix[matrix##i] = safeCalloc(cols, sizeof(type));
+  for (int i = 0; i < rows; ++i) \
+    matrix[i] = safeCalloc(cols, sizeof(type));
 
   // macro for freeing the memory of a matrix 
 #define FREE_MATRIX(matrix, rows) \
-  for (int matrix##i = 0; matrix##i < rows; ++matrix##i) \
-    free(matrix[matrix##i]); \
+  for (int i = 0; i < rows; ++i) \
+    free(matrix[i]); \
   free(matrix);
 
   // macro for reading input into an array of known length
   // Examples:  READ_ARRAY(myInts, "%d", 20);
   //            READ_ARRAY(myDbls, "%lf", 15);
   //            READ_ARRAY(myString, "%c", 10);
 #define READ_ARRAY(arr, format, len) \
-  for (int arr##i = 0; arr##i < len; ++arr##i) \
-    (void)! scanf(format, &arr[arr##i]);
+  for (int i = 0; i < len; ++i) \
+    (void)! scanf(format, &arr[i]);
 
   // macro for reading input into a matrix of given dimensions
   // Examples:  READ_MATRIX(myInts, "%d", 10, 5);
   //            READ_MATRIX(myDbls, "%lf", 8, 8);
   //            READ_MATRIX(myChrs, "%c", 5, 10);
 #define READ_MATRIX(matrix, format, rows, cols) \
-  for (int arr##i = 0; arr##i < rows; ++arr##i) \
-    for (int arr##j = 0; arr##j < cols; ++arr##j) \
-      (void)! scanf(format, &matrix[arr##i][arr##j]);
+  for (int i = 0; i < rows; ++i) \
+    for (int j = 0; j < cols; ++j) \
+      (void)! scanf(format, &matrix[i][j]);
 
   // macro for reading input from stdin as long as it lasts
   // creates a new array of the given type and format,
@@ -92,8 +98,10 @@
   int arr##Len = 0; type arr##var; \
   while (scanf(format, &arr##var) == 1) { \
     arr[arr##Len++] = arr##var; \
-    if (arr##Len % 100 == 0) \
+    if (arr##Len % 100 == 0) {\
       arr = safeRealloc(arr, (arr##Len + 100) * sizeof(type)); \
+      memset(arr + arr##Len, 0, 100 * sizeof(type)); \
+    } \
   } \
   size = arr##Len;\
   arr[arr##Len] = '\0';
@@ -109,8 +117,10 @@
   size_t arr##Len = 0; type arr##var; \
   while (scanf(format, &arr##var) == 1 && arr##var != delim) { \
     arr[arr##Len++] = arr##var; \
-    if (arr##Len % 100 == 0) \
+    if (arr##Len % 100 == 0) { \
       arr = safeRealloc(arr, (arr##Len + 100) * sizeof(type)); \
+      memset(arr + arr##Len, 0, 100 * sizeof(type)); \
+    } \
   } \
   size = arr##Len;\
   arr[arr##Len] = '\0';

IP-Midterms/mid2022/problem1/prob1.c

@@ -6,8 +6,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-#define ABS(x) ((x) < 0 ? -(x) : (x))
-
 void readTime(int time[]){
   for (int i = 0; i < 3; i++){
     time[i] = (getchar() - '0') * 10 + (getchar() - '0');
@@ -24,8 +22,8 @@ int main(int argc, char *argv[]) {
   int diff = (time2[0] - time1[0]) * 3600 + 
     (time2[1] - time1[1]) * 60 + (time2[2] - time1[2]);
 
-  printf("%02d:%02d:%02d\n", ABS(diff / 3600),
-          ABS((diff % 3600) / 60), ABS(diff % 60));
+  printf("%02d:%02d:%02d\n", abs(diff / 3600),
+          abs((diff % 3600) / 60), abs(diff % 60));
 
   return 0;
 }