init

stack.c

@@ -0,0 +1,114 @@
+#include <ctype.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+typedef struct {
+  char key;
+} element;
+element stack[100];
+int top = -1;
+bool isfull() {
+  if (top == 99) {
+    return true;
+  }
+  return false;
+}
+bool isempty() {
+  if (top < 0) {
+    return true;
+  }
+  return false;
+}
+
+void push(char key) {
+  if (isfull()) {
+    printf("stack overflow \n");
+    return;
+  }
+  stack[++top].key = key;
+}
+
+char pop() {
+  if (isempty()) {
+    printf("staxk is empyyt");
+    return '\0';
+  }
+  return stack[top--].key;
+}
+
+int precedence(char op) {
+  switch (op) {
+  case '^':
+    return 3;
+  case '*':
+  case '/':
+    return 2;
+  case '+':
+  case '-':
+    return 1;
+  default:
+    return 0;
+  }
+}
+bool isRight(char op) {
+  if (op == '^') {
+    return true;
+  }
+  return false;
+}
+char peek() {
+  if (isempty()) {
+    printf("stack is empty");
+  }
+  return stack[top].key;
+}
+
+int main() {
+  char infix[100];
+  char postfix[100];
+  printf("enter infix\n");
+  scanf("%s", infix);
+
+  int k = 0;
+  int i = 0;
+
+  while (infix[i] != '\0') {
+    char current = infix[i];
+
+    if (isalpha(current)) {
+      postfix[k++] = current;
+    } else if (current == '(') {
+      push(current);
+    } else if (current == ')') {
+      while (!isempty() && peek() != '(') {
+        postfix[k++] = pop();
+      }
+      if (!isempty() && peek() == '(') {
+        pop(); // Remove '(' from stack
+      }
+    } else { // Operator
+      int currPrec = precedence(current);
+      while (!isempty() && peek() != '(') {
+        char topOp = peek();
+        int topPrec = precedence(topOp);
+
+        if (topPrec > currPrec || (topPrec == currPrec && !isRight(current))) {
+          postfix[k++] = pop();
+        } else {
+          break;
+        }
+      }
+      push(current);
+    }
+    i++;
+  }
+
+  while (!isempty()) {
+    postfix[k++] = pop();
+  }
+
+  postfix[k] = '\0';
+  printf("Postfix: %s\n", postfix);
+
+  return 0;
+}