52 lines
944 B
C
52 lines
944 B
C
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#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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#include <string.h>
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#include <limits.h>
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void itoa(int n, char s[]);
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/* passes arg to itoa or INT_MIN if no arg is given */
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int main(int argc, char *argv[])
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{
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int n;
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if (argc < 2) {
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printf("expected : %d\n", INT_MIN);
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n = INT_MIN;
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} else
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n = atoi(argv[1]);
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char s[(int)log10(INT_MAX) + 3];
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itoa(n, s);
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printf("%s\n", s);
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return 0;
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}
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void reverse(char *s);
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/* itoa: convert n to characters in s */
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void itoa(int n, char s[])
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{
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int i;
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unsigned absn = (n < 0) ? -n : n; /* handles INT_MIN */
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i = 0;
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do {
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s[i++] = absn % 10 + '0';
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} while ((absn /= 10) > 0);
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if (n < 0)
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s[i++] = '-';
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s[i] = '\0';
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reverse(s);
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}
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/* reverse: reverses string s in place */
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void reverse(char *s)
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{
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char c, *s2;
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for (s2 = s + strlen(s) - 1; s < s2; s++, s2--)
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c = *s, *s = *s2, *s2 = c;
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}
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