//-----------------------------------------------------------------------------
// ArithmeticTest.c
// Stubs for required functions.
//-----------------------------------------------------------------------------
#include<stdio.h>
#include<stdlib.h>

// Define fptr_t type using typedef statement
typedef struct (*fptr_t)(int x, int y){
    return 0;
} fptr_t;

// Define functions
int sum(int x, int y){
    return x + y;
}

int diff(int x, int y){
    return x - y;
}

int prod(int x, int y){
    return x * y;
}

int quot(int x, int y){
    return x / y;
}

int rem(int x, int y){
    return x % y;
}

int apply(fptr_t fp, int x, int y){
    return fp(x, y);
}

int compute(fptr_t fp[5], int* opCode, int* operand, int n){
    int x;
    if(n == 1){
        if(opCode[n - 1] == 0){
            x = apply(fp[0], operand[n - 2], operand[n - 1]);
            operand[n - 1] = x;
            return x;
        }
        else if(opCode[n - 1] == 1){
            x = apply(fp[1], operand[n - 2], operand[n - 1]);
            operand[n - 1] = x;
            return x;
        }
        else if(opCode[n - 1] == 2){
            x = apply(fp[2], operand[n - 2], operand[n - 1]);
            operand[n - 1] = x;
            return x;
        }
        else if(opCode[n - 1] == 3){
            x = apply(fp[3], operand[n - 2], operand[n - 1]);
            operand[n - 1] = x;
            return x;
        }
        else if(opCode[n - 1] == 4){
            x = apply(fp[4], operand[n - 2], operand[n - 1]);
            operand[n - 1] = x;
            return x;
        }
    }
    else{
        return compute(fp, opCode, operand, n - 1);
    }
}

void testCompute(){
   fptr_t op[]  = {sum, diff, prod, quot, rem};
   int A[]      = {3, 2, 5, 4, 6, 7, 9, 2, 8};
   int opCode[] = {0, 2, 1, 4, 2, 2, 3, 1};
   int n = 8;

   //--------------------------------------------------------------------------
   // prints 86, which is the value of the value of the expression:
   //
   //               (((((((3+2)*5)-4)%6)*7)*9)/2)-8
   //
   //--------------------------------------------------------------------------
   printf("%d\n", compute(op, A, opCode, n));
}

int main(){
    /*FILE* in;
    int n;
    int* opCode = malloc(255, sizeof(int));
    int* operand = malloc(255, sizeof(int));

    fptr_t fp[] = {sum, diff, prod, quot, rem};

    in = fopen("in1", "r");
    n = fscanf(in, "%d", n);
    fgets(opCode, 255, (FILE*)in);
    fgets(operand, 255, (FILE*)in);

    free(opCode);
    free(operand);*/

    testCompute();
    return EXIT_SUCCESS;
}