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  1. #include <stdio.h>
  2. int c16toi10( char c );
  3. int main( void )
  4. {
  5.     int n;
  6. 	char str[20];
  7. 	char *p;
  8. 	printf("正の16進数の入力 ==>");
  9. 	scanf("%s", str);
  10.  
  11. 	n = 0;
  12. 	p = str;
  13. 	if( c16toi10( *p ) != -1 )
  14. 		n += c16toi10( *p++ );
  15. 	while( c16toi10( *p ) != -1 )
  16. 	{
  17. 		n <<= 4;
  18. 		n += c16toi10( *p++ );
  19. 	}
  20. 	if( *p == '\0' )
  21. 		printf("%s(16) = %d(10)\n", str, n);
  22. 	else
  23. 		printf("ERROR\n");
  24. 	return 0;
  25. }
  26.  
  27. int c16toi10( char c )
  28. {
  29. 	int rtn;
  30. 	if('0' <= c && c <= '9')
  31. 		rtn = c - '0';
  32. 	else if('A' <= c && c <= 'F')
  33. 		rtn = c - 0x37;
  34. 	else if('a' <= c && c <= 'f')
  35. 		rtn = c - 0x57;
  36. 	else
  37. 		rtn = -1;
  38. 	return rtn;
  39. }
Success #stdin #stdout 0.01s 1724KB
comments (?)
stdin 
Standard input is empty
stdout 
正の16進数の入力 ==>ERROR
https://ideone.com/h2F5pk
language:
C (gcc 8.3)
created:
11 years ago
visibility:
public

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