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| Блок кода | ||||||||
|---|---|---|---|---|---|---|---|---|
| ||||||||
//плохо
String result = "0";
for (int i = 1; i < 10000; i++) {
result += "," + i;
}
System.out.println(result);
//хорошо
StringBuilder sb = new StringBuilder("0");
for (int i = 0; i < 10000; i++) {
sb.append(",").append(i);
}
System.out.println(sb.toString()); |
Числа
| Блок кода | ||||||
|---|---|---|---|---|---|---|
| ||||||
double d = 0.1;
double result = 0.0;
for (int i = 0; i < 10; i++) {
result += d;
}
System.out.println("result = " + result);
BigDecimal bc = new BigDecimal(0.1, new MathContext(10, RoundingMode.DOWN));
BigDecimal result = new BigDecimal(0.0, new MathContext(10, RoundingMode.DOWN));
for (int i = 0; i < 10; i++) {
result = result.add(bc);
}
System.out.println("result = " + result); |
Currency
| Блок кода | ||||||
|---|---|---|---|---|---|---|
| ||||||
Currency usd = Currency.getInstance("USD");
Currency eur = Currency.getInstance("EUR");
Currency gbp = Currency.getInstance("GBP");
System.out.println("usd = " + usd);
System.out.println("eur = " + eur);
System.out.println("gbp = " + gbp);
System.out.println(usd.getDisplayName());
System.out.println(usd.getDefaultFractionDigits()); |
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