#include<stdio.h>
#include<stdlib.h>
#include<ctype.h>
#include<string.h>
#define MAX 100
float stk[MAX];
char prefix[] = "-*+923/84";
char new_prefix[MAX];
int top = -1;
void push(float x)
{
    stk[++top] = x;
}
float pop()
{
    return stk[top--];
}
void operation()
{
    int j = 0, i = 0;
    for(i = strlen(prefix) - 1; i >= 0 ; i--)
        new_prefix[j++] = prefix[i];
}
void prefix_eval()
{
    int i = 0, j = 0;
    int op1 = 0, op2 = 0;
    float p = 0, result = 0;
    char x = 0;
    while( new_prefix[i] != '\0')
    {
        x = new_prefix[i];
        if(isdigit(x))
        {
            p = (float)(x - '0');
            push(p);
        }
        else
        {
            op1 = pop();
            op2 = pop();
            if ( x == '+' )
                result = op1 + op2;
            else if ( x == '-')
                result = op1 - op2;
            else if ( x == '*')
                result = op1 * op2;
            else if ( x == '/')
                result = op1 / op2;
            push(result);
        }
        i++;
    }
    printf("The result is: %d", (int)stk[top]);
}


int main()
{
    operation();
    prefix_eval();
    return 0;
}