1 | /* |
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2 | FUNCTION |
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3 | <<itoa>>---integer to string |
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4 | |
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5 | INDEX |
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6 | itoa |
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7 | |
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8 | SYNOPSIS |
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9 | #include <stdlib.h> |
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10 | char *itoa(int <[value]>, char *<[str]>, int <[base]>); |
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11 | char *__itoa(int <[value]>, char *<[str]>, int <[base]>); |
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12 | |
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13 | DESCRIPTION |
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14 | <<itoa>> converts the integer <[value]> to a null-terminated string |
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15 | using the specified base, which must be between 2 and 36, inclusive. |
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16 | If <[base]> is 10, <[value]> is treated as signed and the string will be |
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17 | prefixed with '-' if negative. For all other bases, <[value]> is treated as |
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18 | unsigned. <[str]> should be an array long enough to contain the converted |
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19 | value, which in the worst case is sizeof(int)*8+1 bytes. |
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20 | |
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21 | RETURNS |
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22 | A pointer to the string, <[str]>, or NULL if <[base]> is invalid. |
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23 | |
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24 | PORTABILITY |
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25 | <<itoa>> is non-ANSI. |
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26 | |
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27 | No supporting OS subroutine calls are required. |
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28 | */ |
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29 | |
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30 | #include <stdlib.h> |
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31 | |
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32 | char * |
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33 | __itoa (int value, |
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34 | char *str, |
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35 | int base) |
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36 | { |
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37 | unsigned uvalue; |
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38 | int i = 0; |
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39 | |
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40 | /* Check base is supported. */ |
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41 | if ((base < 2) || (base > 36)) |
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42 | { |
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43 | str[0] = '\0'; |
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44 | return NULL; |
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45 | } |
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46 | |
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47 | /* Negative numbers are only supported for decimal. |
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48 | * Cast to unsigned to avoid overflow for maximum negative value. */ |
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49 | if ((base == 10) && (value < 0)) |
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50 | { |
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51 | str[i++] = '-'; |
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52 | uvalue = (unsigned)-value; |
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53 | } |
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54 | else |
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55 | uvalue = (unsigned)value; |
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56 | |
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57 | __utoa (uvalue, &str[i], base); |
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58 | return str; |
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59 | } |
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60 | |
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61 | char * |
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62 | itoa (int value, |
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63 | char *str, |
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64 | int base) |
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65 | { |
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66 | return __itoa (value, str, base); |
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67 | } |
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