Evaluating Postfix Expression CODE 👇 #include <stdio.h> #include <ctype.h> #define MAX 20 typedef struct { int data[MAX]; int top; }STACK; void initstack(STACK *ps) { ps->top = -1; } void push(STACK *ps, int num) { ps->top++; ps->data[ps->top]=num; } int pop(STACK *ps) { return(ps->data[ps->top--]); } int isempty(STACK *ps) { return(ps->top == -1); } int isfull(STACK *ps) { return(ps->top == MAX-1); } void main() { void Eval(char post[]); char post[20]; printf(">>Evaluating Postfix Expression<<\n"); printf("Enter The Postfix Expression:\t"); scanf("%s", post); Eval(post); } void Eval(char post[]) { int value, i, op1, op2; STACK s1; initstack(&s1); for(i=0; post[i]!='\0'; i++) { if(isalpha(post[i])) { printf("Enter The Value Of %c: \t", post[i]); scanf("%d", &value); push(&s1, value); } else { op2=po...