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  1. BEGIN {
  2.     stack[0] = 0
  3. 	stack_p = 0
  4.  
  5. 	print rpn_calc("3 19 + -2 /")
  6. 	print rpn_calc("3 19 + -2 / +")
  7. 	print rpn_calc("1 2 + 3 4 5 sum")
  8. 	print rpn_calc("5 4 - exp")
  9. 	print rpn_calc("1 2.0 +")
  10. 	print rpn_calc("12 5 /")
  11. 	print rpn_calc("2 3 4 prod")
  12. }
  13.  
  14. function rpn_calc(str,  i, n, q, ql, t) {
  15.  
  16. 	ql = split(str, q)
  17. 	if (! is_integer(q[1])) return 0
  18. 	n = q[1]
  19.  
  20. 	init()
  21. 	for(i = 2; i <= ql; i++) {
  22. 		t = q[i]
  23. 		if (is_integer(t)) {
  24. 			push(n)
  25. 			n = t
  26. 		}
  27. 		else if (t == "+") {
  28. 			if (empty()) return 0
  29. 			n += pop()
  30. 		}
  31. 		else if (t == "-") {
  32. 			if (empty()) return 0
  33. 			n = pop() - n
  34. 		}
  35. 		else if (t == "*") {
  36. 			if (empty()) return 0
  37. 			n *= pop()
  38. 		}
  39. 		else if (t == "/") {
  40. 			if (empty()) return 0
  41. 			n = int(pop() / n)
  42. 		}
  43. 		else if (t == "exp") {
  44. 			n = exp(n)
  45. 		}
  46. 		else if (t == "sum") {
  47. 			while(! empty()) {
  48. 				n += pop()
  49. 			}
  50. 		}
  51. 		else if (t == "prod") {
  52. 			while(! empty()) {
  53. 				n *= pop()
  54. 			}
  55. 		}
  56. 		else {
  57. 			return "error"
  58. 		}
  59. 	}
  60.  
  61. 	return n
  62. }
  63.  
  64. function is_integer(s) {
  65. 	return match(s, /^-?(0|[1-9][0-9]*)$/)
  66. }
  67.  
  68. function init( n) {
  69. 	stack_p = 0
  70. }
  71.  
  72. function push(n) {
  73. 	stack[stack_p++] = n
  74. }
  75.  
  76. function empty( n) {
  77. 	return (stack_p < 1);
  78. }
  79.  
  80. function pop( n) {
  81. 	return (empty() ? 0 : stack[--stack_p])
  82. }
  83.  
Success #stdin #stdout 0.01s 4232KB
comments (?)
stdin
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Standard input is empty
stdout
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-11
0
15
2.71828
error
2
24
https://ideone.com/kwrjvK
language:
AWK (gawk 4.2.1)
created:
12 years ago
visibility:
public

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