fabric_example1.go

// Transaction makes payment of X units from A to B
func (t *ChaincodeExample) MakePayment(stub shim.ChaincodeStubInterface, param *example02.PaymentParams) error {

	var err error

	// Get the state from the ledger
	src, err := t.GetState(stub, param.PartySrc)
	if err != nil {
		return err
	}

	dst, err := t.GetState(stub, param.PartyDst)
	if err != nil {
		return err
	}

	// Perform the execution
	X := int(param.Amount)
	src = src - X
	dst = dst + X
	fmt.Printf("Aval = %d, Bval = %d\n", src, dst)

	// Write the state back to the ledger
	err = stub.PutState(param.PartySrc, []byte(strconv.Itoa(src)))
	if err != nil {
		return err
	}

	err = stub.PutState(param.PartyDst, []byte(strconv.Itoa(dst)))
	if err != nil {
		return err
	}

	return nil
}