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  1. #include <stdio.h>
  2. #include <memory.h>
  3.  
  4. #define BEGIN_HEX 0	/*Íà÷àëî çàïèñè 16-ðè÷íîãî ÷èñëà*/
  5. #define HEX 1		/*Òî÷íî èçâåñòíî, ÷òî ýòî 16-ðè÷íîå ÷èñëî*/
  6. #define NUMBER 2	/* çíà÷àùåé ÷àñòè 16-ðè÷íîãî ÷èñëà*/
  7. #define STRING 3	/*Åñëè ïåðåäàíî íå ÷èñëî, à ëþáàÿ ñòðîêà*/
  8. #define START_PARSING 4
  9.  
  10. int htoi(char s[]);
  11.  
  12. int main(void){
  13. 	int i;
  14.  
  15. 	i = htoi("0x9");
  16. 	printf("%d\n", i);
  17. 	return 0;
  18. }
  19.  
  20. int htoi(char s[]){
  21. 	int res;
  22. 	int i;
  23. 	int state;
  24.  
  25. 	i = res = 0;
  26. 	state = START_PARSING;
  27. 	while(s[i] != '\0'){
  28. 		if(s[i] == '0')
  29. 			if(state == START_PARSING)
  30. 				{state = BEGIN_HEX; printf("state = BEGIN_HEX\n");}
  31. 			else
  32. 				{state == STRING; printf("state = STRING1\n"); }
  33. 		else if(s[i] == 'x')
  34. 			if(state == BEGIN_HEX)
  35. 				{state = HEX; printf("state = HEX\n");}
  36. 			else
  37. 				{state = STRING; printf("state = STRING2\n");}
  38. 		else if(state == HEX){	/*Íà÷èíàåì ðàçáîð 16-ðè÷íîãî ÷èñëà*/
  39. 			if((s[i] >= '0' && s[i] <= '9' ) || (s[i] >= 'A' && s[i] <= 'F')){
  40. 				res = res*16 + (s[i] - '0');
  41. 				printf("s[i] = %d\n", s[i]);
  42. 				printf("s[i] - 0 = %d\n", s[i] - '0');
  43. 			}else{
  44. 				state = STRING;
  45. 				printf("state = STRING");
  46. 			}
  47. 		}
  48. 		i++;	
  49. 	}
  50.  
  51. 	return res;
  52. }
Success #stdin #stdout 0s 3456KB
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state = BEGIN_HEX
state = HEX
s[i] = 57
s[i] - 0 = 9
9
https://ideone.com/vDW1z3
language:
C++ (gcc 8.3)
created:
10 years ago
visibility:
public

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