Merge branch 'master' of https://gitea.joethei.xyz/Studium/Hardwarenahe-Programmierung

src/c/a3.c

@@ -2,27 +2,39 @@
 #include <stdio.h>
 #include <memory.h>
 #include <malloc.h>
+#include <stdint.h>
 
 void memdump(unsigned char *string) {
     printf("ADDR\t\t00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F  0123456789ABCDEF\n");
 
     int columns = 16;
     int rows = 4;
-    char array[columns * rows];
+    char symbols[columns * rows];
+
+    if((long) string % 16 != 0) {
+        string = string - ((long) string % 16);
+    }
+
 
     for(int i = 0; i < rows; i++) {
-        printf("%p\t", (void *) &string[i * columns]);
+        printf("%p\t", (void *) &string[i * columns]);//print address
+
+        if((long) string % 16 != 0) {
+            printf("oh nein, kein mod 16");
+        }
+
 
         for (int j = i * columns; j < (i + 1) * columns; j++) {
-            printf("%02x ", string[j]);
-            if(string[j] < 0x20 || string[j] > 0x7e) array[j] = '.';
-            else array[j] = string[j];
+            printf("%02x ", string[j]);//print char number
+            if(string[j] < 0x20 || string[j] > 0x7e)//check for printable characters
+                symbols[j] = '.';
+            else symbols[j] = string[j];
         }
         printf(" ");
 
+        //print characters
         for (int j = i * columns; j < (i + 1) * columns; j++) {
-            printf("%c", array[j]);
-
+            printf("%c", symbols[j]);
         }
         printf("\n");
     }
@@ -32,10 +44,11 @@ void memdump(unsigned char *string) {
 int memreplace(char *string, char cin, char cout, char **caddr) {
     int found = 0;
     for (int i = 0; i < strlen(string); ++i) {
+        //if char is to be replaced
         if(string[i] == cin) {
+            string[i] = cout;//replace char
             found++;
-            string[i] = cout;
-            *caddr = &string[i];
+            *caddr = &string[i];//setting last found address
         }
     }
     return found;
@@ -47,13 +60,12 @@ int main(int argc, char **argv) {
         return -1;
     }
 
-    memdump((unsigned char *) argv[1]);
+    memdump((unsigned char *) argv[0]);
 
-
-    printf("\tLaenge der Zeichenkette (inkl \\0): %i Byte(s)\n", (int) strlen(argv[1]));
+    printf("\tLaenge der Zeichenkette (inkl \\0): %i Byte(s)\n", (int) strlen(argv[1]) +1);
     printf("\tErsetzen: '%c' mit '%c'\n", *argv[2], *argv[3]);
 
-    unsigned char *copy = malloc(4 * 16 * sizeof(char));
+    unsigned char *copy = malloc(4 * 16 * sizeof(char));//allocate memory for all chars
     strcpy((char *) copy, argv[1]);
 
     char *lastAddress = NULL;