About BigDecimal

Main1.java

double fixedCost = 0.1;
double variableCost = 0.7;

double totalCost = fixedCost + variableCost;

System.out.println(totalCost);
//output: 0.7999999999999999

Main10.java

BigDecimal calculatedRate = calculatedRate.setScale(1, RoundingMode.HALF_UP);

System.out.println(expectedRate.compareTo(calculatedRate) == 0);
//output: true

Main2.java

BigDecimal fixedCost = new BigDecimal(0.1);
BigDecimal variableCost = new BigDecimal(0.7);
		
BigDecimal totalCost = fixedCost.add(variableCost);
		
System.out.println(totalCost);
//output: 0.7999999999999999611421941381195210851728916168212890625

Main3.java

BigDecimal fixedCost = new BigDecimal("0.1");
BigDecimal variableCost = new BigDecimal("0.7");
		
BigDecimal totalCost = fixedCost.add(variableCost);
		
System.out.println(totalCost);
//output: 0.8

Main4.java

BigDecimal totalSalesTwoMonths = new BigDecimal("100.0");
BigDecimal twoMonths = new BigDecimal("2");

BigDecimal avgSalesTwoMonths = totalSalesTwoMonths.divide(twoMonths);

System.out.println(avgSalesTwoMonths);
//output: 50.0

Main5.java

BigDecimal totalSalesQuarter = new BigDecimal("100.0");

BigDecimal threeMonths = new BigDecimal("3");

BigDecimal avgQuarter = totalSalesQuarter.divide(threeMonths);
//output: java.lang.ArithmeticException: Non-terminating decimal expansion; 
//no exact representable decimal result.

Main6.java

BigDecimal avgQuarter = totalSalesQuarter.divide(threeMonths, RoundingMode.HALF_UP);

System.out.println(avgQuarter);
//output: 33.3

Main7.java

//think this "0.0" value came from screen
BigDecimal loss = new BigDecimal("0.0");

//And now I need to check if loss in the month was zero
System.out.println(loss.equals(BigDecimal.ZERO));
//output: false

Main8.java

System.out.println(loss.compareTo(BigDecimal.ZERO) == 0);
//output: true

Main9.java

BigDecimal expectedRate = new BigDecimal("15.5");

BigDecimal calculatedRate = new BigDecimal("15.5178");

System.out.println(expectedRate.compareTo(calculatedRate) == 0);
//output: false