Sample code

modular-contracts

contract Fund is Ownable {

  Calculator calculator;
  uint input1;
  uint input2;
  uint output;
  
  function Fund (address _calculatorAddress) {
    calculator = Calculator(_calculatorAddress);
  }
  
  function calculate() onlyOwner {
    output = calculator.calculate();
  }

  function setCalculator(address _calculatorAddress) onlyOwner returns (bool success) {
    fund = Fund(_calculatorAddress);
    return true;
  }
}

contract Calculator is Ownable {
  Fund fund;
  
  function calculate() onlyFund constant returns (uint output) {
    uint input1 = fund.input1();
    uint input2 = fund.input2();
    
    // Do something
    
    return output;
  }

  function setFund(address _fundAddress) onlyOwner returns (bool success) {
    fund = Fund(_fundAddress);
    return true;
  }
}