Repaired multiply and divide functions & added 2 extra functions

assignment/.vscode/tasks.json

@@ -0,0 +1,28 @@
+{
+    "tasks": [
+        {
+            "type": "cppbuild",
+            "label": "C/C++: gcc build active file",
+            "command": "/usr/bin/gcc",
+            "args": [
+                "-fdiagnostics-color=always",
+                "-g",
+                "${file}",
+                "-o",
+                "${fileDirname}/${fileBasenameNoExtension}"
+            ],
+            "options": {
+                "cwd": "${fileDirname}"
+            },
+            "problemMatcher": [
+                "$gcc"
+            ],
+            "group": {
+                "kind": "build",
+                "isDefault": true
+            },
+            "detail": "Task generated by Debugger."
+        }
+    ],
+    "version": "2.0.0"
+}

assignment/pyramid_of_numbers.c

@@ -29,6 +29,38 @@ struct BigInt {
 	unsigned int the_int[MAX_DIGITS];
 };
 
+/** reset_big_int sets content to 0
+*** @param *big_int The BigInt to be reset
+*** @param startPos The start position where the reset shall begin
+**/
+void reset_big_int(struct BigInt *big_int, int startPos) {
+	if (startPos < 0 || startPos > MAX_DIGITS) {
+		startPos = 0;
+	}
+
+	startPos = MAX_DIGITS - startPos;
+	for (int i = startPos; i >= 0; i--)
+	{
+		big_int->the_int[i] = 0;
+	}
+	big_int->digits_count = 0;
+}
+
+/** set_big_int_length determines the length and sets it
+*** @param *big_int The BigInt to determine the length
+**/
+void set_big_int_length(struct BigInt *big_int)
+{
+	for (int i = 0; i < MAX_DIGITS; i++)
+	{
+		if(big_int->the_int[i] != 0)
+		{
+			big_int->digits_count = MAX_DIGITS - i;
+			return;
+		}
+	}
+}
+
 /** strtobig_int converts a string into a BigInt. If strtobig_int runs
 *** against a character not between '0' and '9' the conversion stops
 *** at this point.
@@ -38,22 +70,28 @@ struct BigInt {
 * @return The number of characters converted.
 */
 int strtobig_int(const char* str, int len, struct BigInt* big_int) {
+	reset_big_int(big_int, -1);
 	int conversions = 0;
-	for (int i = 0; i < len; i++)
+	int j = 0;
+	for (int i = len - 1; i >= 0; i--)
 	{
+		int big_int_position = MAX_DIGITS - j - 1;
 		int converted = str[i] - '0';
 		if (converted >= 0 && converted <= 9)
 		{
-			big_int->the_int[conversions] = converted;
+			big_int->the_int[big_int_position] = converted;
 			conversions++;
 		}
 		else
 		{
 			big_int->digits_count = conversions;
+			//reset_big_int(big_int, conversions);
 			return conversions;
 		}
+		j++;
 	}
 	big_int->digits_count = conversions;
+	//reset_big_int(big_int, conversions);
 	return conversions;
 }
 
@@ -61,7 +99,7 @@ int strtobig_int(const char* str, int len, struct BigInt* big_int) {
 *** @param *big_int The BigInt to be printed.
 */
 void print_big_int(const struct BigInt *big_int) {
-	for (int i = 0; i < big_int->digits_count; i++)
+	for (int i = MAX_DIGITS - big_int->digits_count; i < MAX_DIGITS; i++)
 	{
 		printf("%d", big_int->the_int[i]);
 	}
@@ -73,25 +111,20 @@ void print_big_int(const struct BigInt *big_int) {
 *** @param *big_result The result of the multiplication.
 */
 void multiply(const struct BigInt* big_int, int factor, struct BigInt* big_result) {
-	int overflow = 0;
+	//set everything in the result to 0
-	int sizeOfResult = big_int->digits_count + 1;
+	reset_big_int(big_result, -1);
-	char big_str_result[sizeOfResult];
-	for(int i = 0; i < big_int->digits_count; i++)
-	{
-		int result = big_int->the_int[i] * factor + overflow;
-		if (result > 9)
-		{
-			overflow = result / 10;
-			result = result - overflow;
-		}
-		big_str_result[i] = result + '0';
-	}
-	if (big_str_result[sizeOfResult - 1] == '0')
-	{
-		sizeOfResult--;
-	}
 
-	strtobig_int(big_str_result, sizeOfResult, big_result);
+	//no global overflow needed as it automatically saves it in the next place
+	//no need for '()' braces in the calculation, but used for a better view
+	for (int i = MAX_DIGITS - 1; i >= MAX_DIGITS - big_int->digits_count; i--) {
+		int result = (big_int->the_int[i] * factor) + big_result->the_int[i];
+		int overflow = result / 10;
+		int result_for_i = result - overflow * 10;
+
+		big_result->the_int[i] = result_for_i;
+		big_result->the_int[i - 1] = overflow;
+	}
+	set_big_int_length(big_result);
 }
 
 /** divide() multiplies a BigInt by an int.
@@ -100,24 +133,19 @@ void multiply(const struct BigInt* big_int, int factor, struct BigInt* big_resul
 *** @param *big_result The result of the division.
 */
 void divide(const struct BigInt* big_int, int divisor, struct BigInt* big_result) {
-	int remainder = 0;
+	//set everything in the result to 0
-	int sizeOfResult = big_int->digits_count;
+	reset_big_int(big_result, -1);
-	char str_result[sizeOfResult];
+
-	for (int i = 0; i < big_int->digits_count; i++)
+	//no global remainder needed as the remainder is automatically saved in the big_result
-	{
+	//no need for '()' braces in the calculation, but used for a better view
-		int calculate = remainder * 10;
+	for (int i = MAX_DIGITS - big_int->digits_count; i < MAX_DIGITS; i++) {
-		calculate += big_int->the_int[i];
+		int result = (big_int->the_int[i] + big_result->the_int[i]) / divisor;
-		int result = calculate / divisor;
+		int remainder = big_int->the_int[i] + big_result->the_int[i] - (result * divisor);
-		if (result == 0) {
+
-			remainder = big_int->the_int[i];
+		big_result->the_int[i + 1] = remainder * 10;
-		}
+		big_result->the_int[i] = result;
-		str_result[i] = result + '0';
 	}
-	if (str_result[sizeOfResult - 1] == '0')
+	set_big_int_length(big_result);
-	{
-		sizeOfResult--;
-	}
-	strtobig_int(str_result, sizeOfResult, big_result);
 }
 
 /** copy_big_int() copies a BigInt to another BigInt.
@@ -126,7 +154,7 @@ void divide(const struct BigInt* big_int, int divisor, struct BigInt* big_result
 */
 void copy_big_int(const struct BigInt* from, struct BigInt* to) {
 	to->digits_count = from->digits_count;
-	for (int i = 0; i < from->digits_count; i++) {
+	for (int i = 0; i < MAX_DIGITS; i++) {
 		to->the_int[i] = from->the_int[i];
 	}
 }
@@ -152,6 +180,7 @@ int main(int argc, char* argv[])
 
 	struct BigInt original_big_int;
 	int len = strlen(input_str);
+	reset_big_int(&original_big_int, -1);
 	strtobig_int(input_str, len, &original_big_int);
 
 	struct BigInt changed_big_int;
@@ -175,7 +204,7 @@ int main(int argc, char* argv[])
 	//divide
 	for (int i = 9; i > 1; i--)
 	{
-		//create temp BigInt & multiply
+		//create temp BigInt & divide
 		struct BigInt temp;
 		divide(&changed_big_int, i, &temp);