Create code.c

Postfix to Infix/code.c

@@ -0,0 +1,95 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+
+// Define the maximum size for the stack and expression
+#define MAX 100
+
+// Stack structure to store strings (expressions)
+struct Stack {
+    int top;
+    char* items[MAX];
+};
+
+// Function to initialize the stack
+void initStack(struct Stack* stack) {
+    stack->top = -1;
+}
+
+// Function to push an item onto the stack
+void push(struct Stack* stack, char* str) {
+    if (stack->top >= MAX - 1) {
+        printf("Stack overflow\n");
+        return;
+    }
+    stack->items[++(stack->top)] = strdup(str); // strdup duplicates the string
+}
+
+// Function to pop an item from the stack
+char* pop(struct Stack* stack) {
+    if (stack->top == -1) {
+        printf("Stack underflow\n");
+        return NULL;
+    }
+    return stack->items[(stack->top)--];
+}
+
+// Function to check if a character is an operator
+int isOperator(char ch) {
+    return (ch == '+' || ch == '-' || ch == '*' || ch == '/' || ch == '^');
+}
+
+// Function to convert a Postfix expression to Infix
+void postfixToInfix(char* postfix) {
+    struct Stack stack;
+    initStack(&stack);
+
+    int length = strlen(postfix);
+
+    // Traverse the Postfix expression from left to right
+    for (int i = 0; i < length; i++) {
+        // If the character is an operand, push it onto the stack
+        if (isalnum(postfix[i])) {
+            char operand[2] = {postfix[i], '\0'};  // Create a string for the operand
+            push(&stack, operand);
+        }
+        // If the character is an operator
+        else if (isOperator(postfix[i])) {
+            // Pop the top two operands from the stack
+            char* operand1 = pop(&stack);
+            char* operand2 = pop(&stack);
+
+            // Create a new string: (operand2 operator operand1)
+            char* expression = (char*)malloc(strlen(operand1) + strlen(operand2) + 4);
+            sprintf(expression, "(%s%c%s)", operand2, postfix[i], operand1);
+
+            // Push the resulting expression back onto the stack
+            push(&stack, expression);
+
+            // Free dynamically allocated memory
+            free(operand1);
+            free(operand2);
+        }
+    }
+
+    // The final result is the remaining element in the stack
+    char* result = pop(&stack);
+    printf("Infix Expression: %s\n", result);
+
+    // Free the final result memory
+    free(result);
+}
+
+int main() {
+    char postfix[MAX];
+
+    // Input the Postfix expression
+    printf("Enter a Postfix expression: ");
+    scanf("%s", postfix);
+
+    // Convert and display the Infix expression
+    postfixToInfix(postfix);
+
+    return 0;
+}