added sem 12

1 files changed, 89 insertions, 0 deletions

diff --git a/Sem. 12/task3.cpp b/Sem. 12/task3.cpp
new file mode 100644
index 0000000..ba0ba1b
--- /dev/null
+++ b/Sem. 12/task3.cpp
@@ -0,0 +1,89 @@
+#include <iostream>
+using namespace std;
+
+int search(const char* string, const char* searched);
+
+void replace(const char* string, const char* x, const char* y, char* result)
+{
+	int yLen = strlen(y);
+	int xLen = strlen(x);
+	while (true)
+	{
+		int indX = search(string, x);  //14
+		if (indX == -1)
+			break;
+	
+
+		for (int i = 0; i < indX; i++)
+			result[i] = string[i];
+		result += indX;
+		string += indX + xLen;
+
+		for (int i = 0; i < yLen; i++)
+			result[i] = y[i];
+		result += yLen;
+	}
+
+	//the rest symbols
+	while (*string != '\0')
+	{
+		*result = *string;
+		result++;
+		string++;
+	}
+	*result = '\0';
+
+}
+
+//return the first index of searched in str.
+int search(const char* str, const char* searched) 
+{
+	int len1 = strlen(str);
+	int len2 = strlen(searched);
+	for (int i = 0; i < len1 - len2+1; i++)
+	{
+		bool found = true;
+		for (int j = 0; j < len2; j++)
+		{
+			if (searched[j] != str[i + j])
+			{
+				found = false;
+				break;
+			}
+		}
+		if (found)
+			return i;
+	}
+	return -1;
+}
+int countOccurrences(const char* str, const char* searched)
+{
+	int count = 0;
+
+	int searchLen = strlen(searched);
+	int ind = search(str, searched);
+	while (ind != -1)
+	{
+		count++;
+		str += (ind + searchLen);
+		ind = search(str, searched);
+	}
+	return count;
+}
+int main()
+{
+	const char* str = "hello friends! You are my best friends. I have no other friends";
+	const char* x = "friend";
+	const char* y = "enemy";
+
+	int len = strlen(str);
+	int xOccurrences = countOccurrences(str, x);
+
+	char* result = new char[len - xOccurrences*strlen(x) + xOccurrences*strlen(y) + 1];
+
+	replace(str, x, y, result);
+
+	cout << result << endl;
+	
+	delete[] result;
+}
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