rest of the codes

PostfixEval.c

@@ -0,0 +1,76 @@
+#include<stdio.h>
+#define MAX 40
+
+typedef enum { lparen, rparen, plus, minus, times, divide, mod, eos, operand } precedence;
+
+char EXPR[MAX];
+int stack[20];
+int top = -1;
+
+precedence get_token(char *symbol, int *n)
+{
+    *symbol = EXPR[(*n)++];
+    switch (*symbol)
+    {
+        case '(': return lparen;
+        case ')': return rparen;
+        case '+': return plus;
+        case '-': return minus;
+        case '*': return times;
+        case '/': return divide;
+        case '%': return mod;
+        case '\0': return eos;
+        default:  return operand;
+    }
+}
+
+void push(int num)
+{
+    stack[++top] = num;
+}
+
+int pop()
+{
+    return stack[top--];
+}
+
+int eval()
+{
+    precedence token;
+    char symbol;
+    int op1, op2, n = 0;
+
+    token = get_token(&symbol, &n);
+
+    while (token != eos)
+    {
+        if (token == operand)
+            push(symbol - '0');   // assumes single-digit operands
+        else
+        {
+            op2 = pop();
+            op1 = pop();
+            switch (token)
+            {
+                case plus:   push(op1 + op2); break;
+                case minus:  push(op1 - op2); break;
+                case times:  push(op1 * op2); break;
+                case divide: push(op1 / op2); break;
+                case mod:    push(op1 % op2); break;
+                default:     break;
+            }
+        }
+        token = get_token(&symbol, &n);
+    }
+    return pop();
+}
+
+int main()
+{
+    int res;
+    printf("\nEnter the postfix expression\n");
+    scanf("%s", EXPR);
+    res = eval();
+    printf("\nAfter evaluation:\t%d\n", res);
+    return 0;
+}