finished mini c challenge

challenge.c

@@ -8,7 +8,7 @@
 // Question 0
 // Include the challenge.h header file
 //-------------------------------------------------------------------------
-
+#include "challenge.h"
 
 //-------------------------------------------------------------------------
 // Question 1
@@ -17,14 +17,17 @@
 // of `q1B`should be initialized to 1.
 //-------------------------------------------------------------------------
 
+int q1A = 0;
+int q1B = 1;
 
 //-------------------------------------------------------------------------
 // Question 2
 // Declare a global variable for an integer array of size 10. The name of
 // the array should be `q2Array`. The size should be defined by a macro
 // named `Q2_ARRAY_SIZE`.
 //-------------------------------------------------------------------------
-
+#define Q2_ARRAY_SIZE 10
+int q2Array[Q2_ARRAY_SIZE];
 
 //-------------------------------------------------------------------------
 // Question 3
@@ -37,7 +40,11 @@
 //          The function should return 0b0001001101100101
 //-------------------------------------------------------------------------
 uint16_t q3(uint8_t x, uint8_t y) {
-
+	x ^= 0b10000001;
+	uint16_t result = x;
+	result <<= 8;
+	result += y;
+	return result;
 }
 
 //-------------------------------------------------------------------------
@@ -51,10 +58,16 @@ uint16_t q3(uint8_t x, uint8_t y) {
 // Note: The array contains 8-bit unsigned integers.
 //-------------------------------------------------------------------------
 int32_t q4(uint8_t * array, uint32_t arrayLength) {
-    for (uint8_t i = 0; i <= arrayLength; i++) {
-        int32_t sum = 0;
-        sum += array[i];
-    }
+
+	if ( array == NULL ){
+		return -1;
+	}
+
+	int32_t sum = 0;
+	for (uint32_t i = 0; i < arrayLength; i++) {
+        	sum += array[i];
+    	}
+	return sum;
 }
 
 //-------------------------------------------------------------------------
@@ -63,7 +76,10 @@ int32_t q4(uint8_t * array, uint32_t arrayLength) {
 // - uint32_t a
 // - uint16_t b
 //-------------------------------------------------------------------------
-
+typedef union {
+	uint32_t a;
+	uint16_t b;
+} q5_t;
 
 //-------------------------------------------------------------------------
 // Question 6
@@ -72,7 +88,10 @@ int32_t q4(uint8_t * array, uint32_t arrayLength) {
 // - uint32_t x
 // - uint16_t y
 //-------------------------------------------------------------------------
-
+typedef struct {
+	uint32_t x;
+	uint16_t y;
+} q6_t;
 
 //-------------------------------------------------------------------------
 // Question 7
@@ -81,14 +100,17 @@ int32_t q4(uint8_t * array, uint32_t arrayLength) {
 // - SUCCESS = 0
 // - FAIL = 1
 //-------------------------------------------------------------------------
-
+typedef enum {
+	SUCCESS = 0,
+	FAIL = 1
+} error_t;
 
 //-------------------------------------------------------------------------
 // Question 8
 // Define a macro called `MULTIPLY` that takes two parameters and multiplies
 // them together. The macro should return the result.
 //-------------------------------------------------------------------------
-
+#define MULTIPLY( a, b ) ((a)*(b))
 
 //-------------------------------------------------------------------------
 // Question 9
@@ -101,8 +123,18 @@ int32_t q4(uint8_t * array, uint32_t arrayLength) {
 // q9(&x, &y); // returns 0
 // Now, x = 10 and y = 5
 //-------------------------------------------------------------------------
-int q9(int *a, int *b) {
+#define nullptr NULL
 
+int q9(int *a, int *b) {
+	// won't be able to dereference the variable and will cause an error
+	if ( a == nullptr || b == nullptr ){
+		return -1;
+	} else {
+		int tmp = *a;
+		*a = *b;
+		*b = tmp;
+		return 0;
+	}
 }
 
 //-------------------------------------------------------------------------
@@ -120,7 +152,12 @@ typedef struct {
 } q10_t;
 
 error_t q10(q10_t *q10) {
-
+	int result = q9(&q10->a, &q10->b);
+	if ( result == 0 ){
+		return SUCCESS;
+	} else {
+		return FAIL;
+	}
 }
 
 //-------------------------------------------------------------------------
@@ -143,14 +180,28 @@ typedef struct {
 } q11_b_t;
 
 error_t q11(q11_a_t *a, q11_b_t *b){
-
+	// if either of the pointers is null the we won't be able to access
+	// the values and copy anything
+	if ( a == nullptr || b == nullptr ){
+		return FAIL;
+	}
+
+	// similarly, the arrays of a and b must point to arrays
+	if ( a->array == nullptr || b->array == nullptr ){
+		return FAIL;
+	}
+	for ( int i = 1; i < 51; i++ ){
+		a->array[i - 1] = b->array[i];
+	}
+	return SUCCESS;
 }
 
 //-------------------------------------------------------------------------
 // Question 12
 // Define a macro called `MIN` that takes two parameters and finds the
 // lesser value of the 2. The macro should return the result.
 //-------------------------------------------------------------------------
+#define MIN(a,b) (a < b ? a : b )
 
 //-------------------------------------------------------------------------
 // Question 13
@@ -162,7 +213,18 @@ error_t q11(q11_a_t *a, q11_b_t *b){
 //-------------------------------------------------------------------------
 
 void *q13(uint32_t *ptr1, uint16_t *ptr2){
-
+	// if either pointer is null the comparison will make no sense
+	if ( ptr1 == nullptr || ptr2 == nullptr ){
+		return -1;
+	} else {
+		// convert the addresses to char pointers so we can 
+		// address individual bytes
+		char *char_ptr1 = ptr1;
+		char *char_ptr2 = ptr2;
+		char *min_ptr = char_ptr1 < char_ptr2 ? char_ptr1 : char_ptr2;
+		min_ptr += 5;
+		return min_ptr;
+	}
 }
 //-------------------------------------------------------------------------
 // The following function is used to test your code. Do not remove any 
@@ -273,4 +335,4 @@ int main(void) {
     ASSERT(q13(ptr1, ptr2) == (void *)0x3129);
 
     return 0;
-}
+}