I made a program and I have a problem here.

Problems ::

1. This code accepts 1 digit only if you enter 5 6 + this program shows 11 but it you enter 11 22 + it shows 4. please help me out to change it upto 3 digits.

2. If a user enters 2 operators like 30 40 + * it should display an error "Two operators are not allowed"

3. if user enters 6 2 3 + - 3 8 2 / + * 2 ^ 3 + result 52 should appear.

here is the code.....

Code:#include <stdio.h> #include <ctype.h> #include <iostream> #include <stdlib.h> #include <string> #include <sstream> #include <fstream> #include <cstdio> #include <iomanip> #include <cstdlib> #define MAX 50 #define EMPTY -1 struct stack { int data[MAX]; int top; }; void emptystack(struct stack* s) { s->top = EMPTY; } void push(struct stack* s,int item) { if(s->top == (MAX-1)) { printf("\nSTACK FULL"); } else { ++s->top; s->data[s->top]=item; } } int pop(struct stack* s) { int ret=EMPTY; if(s->top == EMPTY) printf("\nSTACK EMPTY"); else { ret= s->data[s->top]; --s->top; } return ret; } void display(struct stack s) { while(s.top != EMPTY) { printf("\n%d",s.data[s.top]); s.top--; } } int evaluate(char *postfix) { char *p; struct stack stk; int op1,op2,result; emptystack(&stk); p = &postfix[0]; while(*p != '\0') { /* removes tabs and spaces */ while(*p == ' ' || *p == '\t') { p++; } /* if is digit */ if(isdigit(*p)) { push(&stk,*p - 48); } else { /* it is an operator */ op1 = pop(&stk); op2 = pop(&stk); switch(*p) { case '+': result = op2 + op1; break; case '-': result = op2 - op1; break; case '/': result = op2 / op1; break; case '*': result = op2 * op1; break; case '%': result = op2 % op1; break; case '^': result = op2 ^ op1; break; default: printf("\nInvalid Operator"); return 0; } push(&stk,result); } p++; } result = pop(&stk); return result; } int main() { char exp[MAX]; printf("Enter Postfix Exp<b></b>ression : "); gets(exp); printf("%s EQUALS %d\n",exp,evaluate(&exp[0])); gets(exp); return 0; }