Examples

Program Listing 3-7 is a complete program that illustrates the use of format verbs and flags with the print function:

Program Listing 3-7 iox.b

1. implement Command;
3. include "sys.m";
4. include "draw.m";
6. sys: Sys;
8. Command: module {
9. init: fn(ctxt: ref Draw->Context, argv: list of string);
10. };
12. init(ctxt: ref Draw->Context, argv: list of string) {
13. sys = load Sys Sys->PATH;
15. num := 123;
16. decnum := 2345.678901;
17. scinum := 0.0000987;
18. str := "Hello, Inferno!";
20. # field width
21. for (i := 1; i <= 5; i++) {
22. sys->print("%8d %8d %8d %8d %8d\n",
23. i, i*i, i*i*i, i*i*i*i, i*i*i*i*i);
24. }
26. sys->print("%d\n", num);
27. sys->print("%10d\n\n", num);
29. # precision
30. sys->print("%.3f\n", decnum);
31. sys->print("%2.5d\n", num);
32. sys->print("%5.10s\n\n", str);
34. # scientific notation
35. sys->print("%e\n", scinum);
36. sys->print("%E\n", decnum);
37. sys->print("%g\n", decnum);
38. sys->print("%g\n\n", scinum);
40. # justification
41. sys->print("Right-justified: %5d\n", num);
42. sys->print("Left-justified: %-5d\n", num);
43. sys->print("$%9.2f\n\n", decnum);
45. # Decimal and Hexadecimal
46. sys->print("%#d\n", num);
47. sys->print("%x\n", num);
48. sys->print("%#X\n", num);
49. }

		1        1        1        1        1
		2        4        8       16       32
		3        9       27       81      243
		4       16       64      256     1024
		5       25      125      625     3125
123
       123

2345.679
00123
Hello, Inf

9.870000e-05
2.345679E+03
2345.678901
9.87e-05

Right-justified:   123
Left-justified: 123  
$  2345.68

123.0
7b
0X7B