program5a

#include<stdio.h>
#include<math.h>
#include<ctype.h>
float stack[50];
int top = -1;

void push(float x) {
    stack[++top] = x;
}

float pop() {
    return stack[top--];
}

float eval(char postfix[]) {
    float op1, op2, res;
    char ch;
    int i = 0;
    while ((ch = postfix[i]) != '\0') {
        if (isdigit(ch)) {
            push(ch - '0');
        } else {
            op2 = pop();
            op1 = pop();
            res = oper(ch, op1, op2);
            push(res);
        }
        i++;
    }
    return pop();
}

float oper(char symb, float op1, float op2) {
    switch(symb) {
        case '$':
        case '^': return pow(op1, op2);
        case '*': return op1 * op2;
        case '/': return op1 / op2;
        case '+': return op1 + op2;
        case '-': return op1 - op2;
        default: return 0;
    }
}

int main() {
    char postfix[50];
    int choice;
    float res;
    do {
        printf("Enter postfix expression: ");
        scanf("%s", postfix);
        res = eval(postfix);
        printf("Result = %f\n", res);
        printf("Do you want to enter another expression? (1/0): ");
        scanf("%d", &choice);
    } while (choice != 0);
    return 0;
}