Merge pull request #890 from Panquesito7/lgtm_fixes

fix: Various LGTM fixes

data_structures/stack_using_array.cpp

@@ -1,37 +1,38 @@
 #include <iostream>
 
 int *stack;
-int top = 0, stack_size;
+int stack_idx = 0, stack_size;
 
 void push(int x) {
-    if (top == stack_size) {
+    if (stack_idx == stack_size) {
         std::cout << "\nOverflow";
     } else {
-        stack[top++] = x;
+        stack[stack_idx++] = x;
     }
 }
 
 void pop() {
-    if (top == 0) {
+    if (stack_idx == 0) {
         std::cout << "\nUnderflow";
     } else {
-        std::cout << "\n" << stack[--top] << " deleted";
+        std::cout << "\n" << stack[--stack_idx] << " deleted";
     }
 }
 
 void show() {
-    for (int i = 0; i < top; i++) {
+    for (int i = 0; i < stack_idx; i++) {
         std::cout << stack[i] << "\n";
     }
 }
 
-void topmost() { std::cout << "\nTopmost element: " << stack[top - 1]; }
+void topmost() { std::cout << "\nTopmost element: " << stack[stack_idx - 1]; }
 int main() {
     std::cout << "\nEnter stack_size of stack : ";
     std::cin >> stack_size;
     stack = new int[stack_size];
     int ch, x;
     do {
+        std::cout << "\n0. Exit";
         std::cout << "\n1. Push";
         std::cout << "\n2. Pop";
         std::cout << "\n3. Print";
@@ -51,5 +52,7 @@ int main() {
         }
     } while (ch != 0);
 
+    delete[] stack;
+
     return 0;
 }

data_structures/stack_using_linked_list.cpp

@@ -1,35 +1,34 @@
 #include <iostream>
-using namespace std;
 
 struct node {
     int val;
     node *next;
 };
 
-node *top;
+node *top_var;
 
 void push(int x) {
     node *n = new node;
     n->val = x;
-    n->next = top;
-    top = n;
+    n->next = top_var;
+    top_var = n;
 }
 
 void pop() {
-    if (top == NULL) {
-        cout << "\nUnderflow";
+    if (top_var == NULL) {
+        std::cout << "\nUnderflow";
     } else {
-        node *t = top;
-        cout << "\n" << t->val << " deleted";
-        top = top->next;
+        node *t = top_var;
+        std::cout << "\n" << t->val << " deleted";
+        top_var = top_var->next;
         delete t;
     }
 }
 
 void show() {
-    node *t = top;
+    node *t = top_var;
     while (t != NULL) {
-        cout << t->val << "\n";
+        std::cout << t->val << "\n";
         t = t->next;
     }
 }
@@ -37,14 +36,14 @@ void show() {
 int main() {
     int ch, x;
     do {
-        cout << "\n1. Push";
-        cout << "\n2. Pop";
-        cout << "\n3. Print";
-        cout << "\nEnter Your Choice : ";
-        cin >> ch;
+        std::cout << "\n1. Push";
+        std::cout << "\n2. Pop";
+        std::cout << "\n3. Print";
+        std::cout << "\nEnter Your Choice : ";
+        std::cin >> ch;
         if (ch == 1) {
-            cout << "\nInsert : ";
-            cin >> x;
+            std::cout << "\nInsert : ";
+            std::cin >> x;
             push(x);
         } else if (ch == 2) {
             pop();