?? format.java
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if (precision < 0) precision = 6;
int s = 1;
if (x < 0) { x = -x; s = -1; }
if (fmt == 'f')
r = fixed_format(x);
else if (fmt == 'e' || fmt == 'E' || fmt == 'g' || fmt == 'G')
r = exp_format(x);
else throw new java.lang.IllegalArgumentException();
return pad(sign(s, r));
}
/**
Formats an integer into a string (like sprintf in C)
@param x the number to format
@return the formatted string
*/
public String format(int x)
{ long lx = x;
if (fmt == 'o' || fmt == 'x' || fmt == 'X')
lx &= 0xFFFFFFFFL;
return format(lx);
}
/**
Formats a long integer into a string (like sprintf in C)
@param x the number to format
@return the formatted string
*/
public String format(long x)
{ String r;
int s = 0;
if (fmt == 'd' || fmt == 'i')
{ if (x < 0)
{ r = ("" + x).substring(1);
s = -1;
}
else
{ r = "" + x;
s = 1;
}
}
else if (fmt == 'o')
r = convert(x, 3, 7, "01234567");
else if (fmt == 'x')
r = convert(x, 4, 15, "0123456789abcdef");
else if (fmt == 'X')
r = convert(x, 4, 15, "0123456789ABCDEF");
else throw new java.lang.IllegalArgumentException();
return pad(sign(s, r));
}
/**
Formats a character into a string (like sprintf in C)
@param x the value to format
@return the formatted string
*/
public String format(char c)
{ if (fmt != 'c')
throw new java.lang.IllegalArgumentException();
String r = "" + c;
return pad(r);
}
/**
Formats a string into a larger string (like sprintf in C)
@param x the value to format
@return the formatted string
*/
public String format(String s)
{ if (fmt != 's')
throw new java.lang.IllegalArgumentException();
if (precision >= 0 && precision < s.length())
s = s.substring(0, precision);
return pad(s);
}
/**
a test stub for the format class
*/
public static void main(String[] a)
{ double x = 1.23456789012;
double y = 123;
double z = 1.2345e30;
double w = 1.02;
double u = 1.234e-5;
int d = 0xCAFE;
Format.printf("x = |%f|\n", x);
Format.printf("u = |%20f|\n", u);
Format.printf("x = |% .5f|\n", x);
Format.printf("w = |%20.5f|\n", w);
Format.printf("x = |%020.5f|\n", x);
Format.printf("x = |%+20.5f|\n", x);
Format.printf("x = |%+020.5f|\n", x);
Format.printf("x = |% 020.5f|\n", x);
Format.printf("y = |%#+20.5f|\n", y);
Format.printf("y = |%-+20.5f|\n", y);
Format.printf("z = |%20.5f|\n", z);
Format.printf("x = |%e|\n", x);
Format.printf("u = |%20e|\n", u);
Format.printf("x = |% .5e|\n", x);
Format.printf("w = |%20.5e|\n", w);
Format.printf("x = |%020.5e|\n", x);
Format.printf("x = |%+20.5e|\n", x);
Format.printf("x = |%+020.5e|\n", x);
Format.printf("x = |% 020.5e|\n", x);
Format.printf("y = |%#+20.5e|\n", y);
Format.printf("y = |%-+20.5e|\n", y);
Format.printf("x = |%g|\n", x);
Format.printf("z = |%g|\n", z);
Format.printf("w = |%g|\n", w);
Format.printf("u = |%g|\n", u);
Format.printf("y = |%.2g|\n", y);
Format.printf("y = |%#.2g|\n", y);
Format.printf("d = |%d|\n", d);
Format.printf("d = |%20d|\n", d);
Format.printf("d = |%020d|\n", d);
Format.printf("d = |%+20d|\n", d);
Format.printf("d = |% 020d|\n", d);
Format.printf("d = |%-20d|\n", d);
Format.printf("d = |%20.8d|\n", d);
Format.printf("d = |%x|\n", d);
Format.printf("d = |%20X|\n", d);
Format.printf("d = |%#20x|\n", d);
Format.printf("d = |%020X|\n", d);
Format.printf("d = |%20.8x|\n", d);
Format.printf("d = |%o|\n", d);
Format.printf("d = |%020o|\n", d);
Format.printf("d = |%#20o|\n", d);
Format.printf("d = |%#020o|\n", d);
Format.printf("d = |%20.12o|\n", d);
Format.printf("s = |%-20s|\n", "Hello");
Format.printf("s = |%-20c|\n", '!');
// regression test to confirm fix of reported bugs
Format.printf("|%i|\n", Long.MIN_VALUE);
Format.printf("|%6.2e|\n", 0.0);
Format.printf("|%6.2g|\n", 0.0);
Format.printf("|%6.2f|\n", 9.99);
Format.printf("|%6.2f|\n", 9.999);
Format.printf("|%6.0f|\n", 9.999);
d = -1;
Format.printf("d = |%X|\n", d);
}
private static String repeat(char c, int n)
{ if (n <= 0) return "";
StringBuffer s = new StringBuffer(n);
for (int i = 0; i < n; i++) s.append(c);
return s.toString();
}
private static String convert(long x, int n, int m, String d)
{ if (x == 0) return "0";
String r = "";
while (x != 0)
{ r = d.charAt((int)(x & m)) + r;
x = x >>> n;
}
return r;
}
private String pad(String r)
{ String p = repeat(' ', width - r.length());
if (left_align) return pre + r + p + post;
else return pre + p + r + post;
}
private String sign(int s, String r)
{ String p = "";
if (s < 0) p = "-";
else if (s > 0)
{ if (show_plus) p = "+";
else if (show_space) p = " ";
}
else
{ if (fmt == 'o' && alternate && r.length() > 0 && r.charAt(0) != '0') p = "0";
else if (fmt == 'x' && alternate) p = "0x";
else if (fmt == 'X' && alternate) p = "0X";
}
int w = 0;
if (leading_zeroes)
w = width;
else if ((fmt == 'd' || fmt == 'i' || fmt == 'x' || fmt == 'X' || fmt == 'o')
&& precision > 0) w = precision;
return p + repeat('0', w - p.length() - r.length()) + r;
}
private String fixed_format(double d)
{ boolean removeTrailing
= (fmt == 'G' || fmt == 'g') && !alternate;
// remove trailing zeroes and decimal point
if (d > 0x7FFFFFFFFFFFFFFFL) return exp_format(d);
if (precision == 0)
return (long)(d + 0.5) + (removeTrailing ? "" : ".");
long whole = (long)d;
double fr = d - whole; // fractional part
if (fr >= 1 || fr < 0) return exp_format(d);
double factor = 1;
String leading_zeroes = "";
for (int i = 1; i <= precision && factor <= 0x7FFFFFFFFFFFFFFFL; i++)
{ factor *= 10;
leading_zeroes = leading_zeroes + "0";
}
long l = (long) (factor * fr + 0.5);
if (l >= factor) { l = 0; whole++; } // CSH 10-25-97
String z = leading_zeroes + l;
z = "." + z.substring(z.length() - precision, z.length());
if (removeTrailing)
{ int t = z.length() - 1;
while (t >= 0 && z.charAt(t) == '0') t--;
if (t >= 0 && z.charAt(t) == '.') t--;
z = z.substring(0, t + 1);
}
return whole + z;
}
private String exp_format(double d)
{ String f = "";
int e = 0;
double dd = d;
double factor = 1;
if (d != 0)
{ while (dd > 10) { e++; factor /= 10; dd = dd / 10; }
while (dd < 1) { e--; factor *= 10; dd = dd * 10; }
}
if ((fmt == 'g' || fmt == 'G') && e >= -4 && e < precision)
return fixed_format(d);
d = d * factor;
f = f + fixed_format(d);
if (fmt == 'e' || fmt == 'g')
f = f + "e";
else
f = f + "E";
String p = "000";
if (e >= 0)
{ f = f + "+";
p = p + e;
}
else
{ f = f + "-";
p = p + (-e);
}
return f + p.substring(p.length() - 3, p.length());
}
private int width;
private int precision;
private String pre;
private String post;
private boolean leading_zeroes;
private boolean show_plus;
private boolean alternate;
private boolean show_space;
private boolean left_align;
private char fmt; // one of cdeEfgGiosxXos
}?? 快捷鍵說明
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