I love FIIT

arrays.cpp

@@ -1,9 +1,6 @@
 #include <iostream>
 #include <cassert>
 
-#if 0
-// NOTE: you should move this `if` down as you start solving each task
-
 void task_1()
 {
     /* Task 1: find a bug in the following declaration.
@@ -12,17 +9,17 @@ void task_1()
      * pedantic flag here means: strictly as in language standard 
      * for explanation see:
      *  https://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html*/
-    int n = 10;
+    const int n = 10;
     int a[n];
 }
 
 // Task 2
 void task_2()
 {
     int a[5] = {0};
-    
-    //assert(!a[4]) or assert(a[4]) -- place here one of these and
-    //                                 explain your choice in commit msg
+	assert(!a[4]);
+	//place here one of these and
+    //explain your choice in commit msg
 }
 
 // returns zero
@@ -31,7 +28,7 @@ int task_3_zero()
     // Task 3
     // Hint 1: fix with initialization (not assignment)
     // Hint 2: you can use only one zero and not five of them! cf. task 2
-    int a[5];
+	int a[5] = { 0 };
 
     assert(!a[4]);
     return a[4]; // don't touch this!
@@ -41,7 +38,7 @@ void task_4()
 {
     // Task 4: asserts at the end must hold
     // Hint: fix with initialization (not assignment)
-    int a[5];
+	int a[5]{1, 2, 3, 4, 5};
 
     assert(a[0] == 1);
     assert(a[1] == 2);
@@ -54,15 +51,17 @@ void task_4()
 // copy arr1 to arr2
 void task_5_copy(int * arr1, int * arr2, int size)
 {
-    arr2 = arr1;
+	for (int i = 0; i < size; i++)
+	{
+		arr2[i] = arr1[i];
+	}
 }
 
 // Task 6
 // copy array `arr1` to array `arr2` of the same size
-void task_6_poor_copy(int * arr1, int * arr2)
+void task_6_poor_copy(int * arr1, int * arr2, int size)
 {
-    // Hint: something wrong here; test this from main()
-    for(int i = 0; i < sizeof(arr2); ++i)
+    for(int i = 0; i < size; ++i)
     {
         arr2[i] = arr1[i];
     }
@@ -72,11 +71,9 @@ void task_6_poor_copy(int * arr1, int * arr2)
 // print array `arr`
 void task_7_print(int * arr, int size, char delim = ' ')
 {
-    // Hint: something wrong here; run this from main()
-    for(int i = 0; i <= size; ++i)
+    for(int i = 0; i < size; ++i)
     {
-        std::cout << a[i] << delim;
+        std::cout << arr[i] << delim;
     }
-}
-
-#endif
+	std::cout << std::endl;
+}

arrays.h

@@ -0,0 +1,21 @@
+#ifndef _ARRAYS
+#define _ARRAYS
+
+void task_1();
+
+void task_2();
+
+int task_3_zero();
+
+void task_4();
+
+// copy arr1 to arr2
+void task_5_copy(int * arr1, int * arr2, int size);
+
+// copy array `arr1` to array `arr2` of the same size
+void task_6_poor_copy(int * arr1, int * arr2, int size);
+
+// print array `arr`
+void task_7_print(int * arr, int size, char delim = ' ');
+
+#endif

count.cpp

@@ -1,37 +1,46 @@
 #include <string>
 #include <cstdio>
+#include <iostream>
 
 using namespace std;
 
-/* count digits, white space, others */
-
-/* TODO: (1) fix all errors; 
- *       (2) add code for painting histogram in console,
- *           cf. picture in https://en.wikipedia.org/wiki/Histogram
- * 
- */
-
 int main()
 {
 	string src("12 plus 45 minus 39 is 18\n");
-	int i, nwhite, nother;
+	int nwhite, nother;
 	const int size = 10;
-	int ndigit[size];
+	int ndigit[size]{0};
 	nwhite = nother = 0;
 
 	char c;
-	while ((c = src[i++]) != EOF)
-		if (c >= '0' && c >= '9')
+
+	for (int j = 0; j < src.length(); j ++)
+	{
+		c = src[j];
+
+		if (c >= '0' && c <= '9')
 			++ndigit[c - '0'];
-		else if (c == ' ' && c == '\n' && c == '\t')
+		else if (c == ' ' || c == '\n' || c == '\t')
 			++nwhite;
 		else
 			++nother;
+	}
 
 	cout << "source string: " << src << endl << "digits =";
 	for (int i = 0; i < size; ++i)
 		cout << " " << ndigit[i];
 
 	cout << ", white space = " << nwhite 
-		 << ", other = " << nother << endl;
+		 << ", other = " << nother << endl << endl;
+
+	cout << "table:\n";
+	for (int i = 0; i < size; i++)
+	{
+		cout << "symbol " << i << " contains " << ndigit[i] << " times\n";
+	}
+
+	cout << "white space" << " contains " << nwhite << " times\n";
+	cout << "others" << " contains " << nother << " times\n";
+
+	system("pause");
 }

main.cpp

@@ -0,0 +1,31 @@
+#include <iostream>
+#include <cassert>
+#include "arrays.h"
+
+using namespace std;
+
+int main()
+{
+	task_1();
+	task_2();
+	task_3_zero();
+	task_4();
+
+	int a[3]{1, 2, 3};
+	int b[3];
+	int c[3];
+
+	task_5_copy(a, b, 3);
+	assert(a[0] == 1);
+	assert(a[1] == 2);
+	assert(a[2] == 3);
+
+	task_6_poor_copy(a, c, 3);
+	assert(c[0] == 1);
+	assert(c[1] == 2);
+	assert(c[2] == 3);
+
+	task_7_print(a,3);
+
+	system("pause");
+}

quick_sort.cpp

@@ -1,28 +1,58 @@
 #include <iostream>
-
 #include <cstdlib>
 
 using std::rand;
 using std::swap;
+using std::cout;
 
 // pivot - "опорный" элемент
 // partition - переупорядочивает элементы части массива,
 // заданной отрезком [left, right), так что в начале
 // следуют элементы меньшие pivot, а в конце - большие;
 // возвращает место начала блока элементов, больших pivot;
-int * partition(int * left, int *  right, int pivot) {
+int * partition(int * left, int * right, int pivot) 
+{
 	int * store = left; // место для вставки элементов, меньших pivot
 	for (int * p = left; p != right; ++p)
-		if (*p < pivot)
+		if (*p <= pivot)
 			swap(*p, *store++);
 	return store;
 }
 
-void my_qsort(int * arr, int n) {
+void my_qsort(int * arr, int n) 
+{
 	if (n <= 1)
 		return; // массив в 1 или 0 элементов уже упорядочен
 	int * pivotPtr = arr + rand() % n; // случайный выбор опорного элемента
 	int newPivotIdx = partition(arr, arr + n, *pivotPtr) - arr;
-	my_qsort(arr, newPivotIdx + 1);
-	my_qsort(arr + newPivotIdx, n - (newPivotIdx + 1));
+	my_qsort(arr, newPivotIdx);
+	my_qsort(arr + newPivotIdx, n - newPivotIdx);
+}
+
+void println(int *a, int n)
+{
+	for (int i = 0; i < n; i++)
+	{
+		cout << a[i] << " ";
+	}
+	cout << "\n";
 }
+
+int main()
+{
+	const int m = 9;
+	int a[m]{666, 1, 3, 2, 5, 4, 0, -666, 99};
+	println(a, m);
+	my_qsort(a, m);
+	println(a, m);
+	cout << "\n";
+
+	const int n = 5;
+	int b[n]{1, 666, -666, 0, 2};
+	println(b, n);
+	my_qsort(b, n);
+	println(b, n);
+	cout << "\n";
+
+	system("pause");
+}