AP

1.cpp

@@ -2,24 +2,33 @@
 using namespace std;
 
 class container {
-
+protected:
 	int size;
 public:
 	float* p;
+	container(){
+
+	}
 	container(int s) :size(s){}
 	const int& getsize() { return size;}
+	void set_size(int size){
+		this->size = size;
+	}
 
 };
 
 class vector :public container {
 
 	int call_num;
 public:
-	explicit vector(int l) :len(l),size(1 * 100){
+	vector(){
+
+	}
+	explicit vector(int l) :len(l),container(1 * 100){
 		p = new float();
 	}
 	int len;
-	int& getlen() const {
+	int& getlen(){
 		call_num ++;
 		return len;
 	}
@@ -29,12 +38,13 @@ class vector :public container {
 int main() {
 
 	container c1(100);
-	vector v1 = c1;
+	vector v1 = (vector)c1;
 	container& r1 = v1;
 	container c2 = 100;
-	c2.getsize() = 20;
+	c2.set_size(20);//set function 
+	c2.getsize();
 	cout << c2.getsize();
-	vector v2 = 100;
-	v2.getlen = 40;
+	vector v2{100};
+	v2.getlen() = 40;
 	cout << v2.getlen();
 }

2.cpp

@@ -5,11 +5,11 @@ using namespace std;
 
 // count all the specific char in the whole array of strings
 int countAllSpecificChars(string sArr[], int arrLength, char specificChar) {
-    int count;
-    for (int i = 0; i <= arrLength; ++i)
-        for (int j = 0; j <= sArr[i].size(); ++j)
+    int count = 0;
+    for (int i = 0; i < arrLength; i++)//i++    i < arrLength
+        for (int j = 0; j < sArr[i].size(); j++)//j++ j < sArr[i].size()
             // if the jth char of the string is the specific char
-            if (sArr[i][j] = specificChar)
+            if (sArr[i][j] == specificChar)//==
                 count++;
     return count;
 }

4.cpp

@@ -6,4 +6,5 @@ int main()
     float *ptr2 = ptr1 + 3;
     printf("%f", *ptr2 - *ptr1);
     return 0;
-}
+}
+//78.000 will print

5.cpp

@@ -7,4 +7,6 @@ int main()
     printf("%d\n", (*ptr2 - *ptr1));
     printf("%c", (char)(*ptr2 - *ptr1));
     return 0;
-}
+}
+//50 will print
+//2 will print

6.cpp

@@ -9,3 +9,4 @@ int main()
 	printf("%d\n", a);
 	return 0;
 }
+//513 will print

7.cpp

@@ -7,4 +7,5 @@ int main()
 	p += 2;
 	printf("%d", *p);
 	return 0;
-}
+}
+//3 will print