fix: Various LGTM fixes

data_structures/stack_using_array.cpp

@@ -1,31 +1,31 @@
 #include <iostream>
 
 int *stack;
-int top = 0, stack_size;
+int top_var = 0, stack_size;
 
 void push(int x) {
-    if (top == stack_size) {
+    if (top_var == stack_size) {
         std::cout << "\nOverflow";
     } else {
-        stack[top++] = x;
+        stack[top_var++] = x;
     }
 }
 
 void pop() {
-    if (top == 0) {
+    if (top_var == 0) {
         std::cout << "\nUnderflow";
     } else {
-        std::cout << "\n" << stack[--top] << " deleted";
+        std::cout << "\n" << stack[--top_var] << " deleted";
     }
 }
 
 void show() {
-    for (int i = 0; i < top; i++) {
+    for (int i = 0; i < top_var; i++) {
         std::cout << stack[i] << "\n";
     }
 }
 
-void topmost() { std::cout << "\nTopmost element: " << stack[top - 1]; }
+void topmost() { std::cout << "\nTopmost element: " << stack[top_var - 1]; }
 int main() {
     std::cout << "\nEnter stack_size of stack : ";
     std::cin >> stack_size;

data_structures/stack_using_linked_list.cpp

@@ -6,28 +6,28 @@ struct node {
     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) {
+    if (top_var == NULL) {
         cout << "\nUnderflow";
     } else {
-        node *t = top;
+        node *t = top_var;
         cout << "\n" << t->val << " deleted";
-        top = top->next;
+        top_var = top_var->next;
         delete t;
     }
 }
 
 void show() {
-    node *t = top;
+    node *t = top_var;
     while (t != NULL) {
         cout << t->val << "\n";
         t = t->next;

math/fibonacci_fast.cpp

@@ -24,23 +24,23 @@
 const uint64_t MAX = 93;
 
 /** Array of computed fibonacci numbers */
-uint64_t f[MAX] = {0};
+uint64_t numbers[MAX] = {0};
 
 /** Algorithm */
 uint64_t fib(uint64_t n) {
     if (n == 0)
         return 0;
     if (n == 1 || n == 2)
-        return (f[n] = 1);
+        return (numbers[n] = 1);
 
-    if (f[n])
-        return f[n];
+    if (numbers[n])
+        return numbers[n];
 
     uint64_t k = (n % 2 != 0) ? (n + 1) / 2 : n / 2;
 
-    f[n] = (n % 2 != 0) ? (fib(k) * fib(k) + fib(k - 1) * fib(k - 1))
+    numbers[n] = (n % 2 != 0) ? (fib(k) * fib(k) + fib(k - 1) * fib(k - 1))
                         : (2 * fib(k - 1) + fib(k)) * fib(k);
-    return f[n];
+    return numbers[n];
 }
 
 /** Main function */

others/paranthesis_matching.cpp

@@ -20,13 +20,13 @@
 char stack[MAX];
 
 //! pointer to track stack index
-int top = -1;
+int top_var = -1;
 
 //! push byte to stack variable
-void push(char ch) { stack[++top] = ch; }
+void push(char ch) { stack[++top_var] = ch; }
 
 //! pop a byte out of stack variable
-char pop() { return stack[top--]; }
+char pop() { return stack[top_var--]; }
 
 //! @}-------------- end stack -----------
 
@@ -56,7 +56,7 @@ int main() {
     while (valid == 1 && i < exp.length()) {
         if (exp[i] == '(' || exp[i] == '{' || exp[i] == '[' || exp[i] == '<') {
             push(exp[i]);
-        } else if (top >= 0 && stack[top] == opening(exp[i])) {
+        } else if (top_var >= 0 && stack[top_var] == opening(exp[i])) {
             pop();
         } else {
             valid = 0;
@@ -65,7 +65,7 @@ int main() {
     }
 
     // makes sure the stack is empty after processsing (above)
-    if (valid == 1 && top == -1) {
+    if (valid == 1 && top_var == -1) {
         std::cout << "\nCorrect Expression";
     } else {
         std::cout << "\nWrong Expression";