kdeng00
67 lines
1.1 KiB
C
67 lines
1.1 KiB
C
/*
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*
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* Exercise 1-19. Write a function reverse(s) that reverses the character string s.
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* Use it to write a program that reverses its input a line at a time.
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*
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* Author: Kun Deng
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*/
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#include <stdio.h>
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#define UPPER 200
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#define LOWER 0
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#define STEP 10
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#define LINE_MAX_LIMIT 1000
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int get_line(char line[]);
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void reverse(char whole_string[], int length);
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int main(int argc, char **argv)
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{
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char line[LINE_MAX_LIMIT];
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int length;
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while ((length = get_line(line)))
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{
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printf("before: %s\n", line);
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reverse(line, length);
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printf("after: %s\n", line);
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}
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return 0;
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}
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int get_line(char line[])
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{
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int i = 0;
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int c;
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for (; ((c = getchar()) != EOF) && c != '\n'; ++i)
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{
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line[i] = c;
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}
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line[i] = '\0';
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return i;
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}
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void reverse(char whole_string[], int length)
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{
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int mirrored_index = length - 1;
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for (int i = 0; i != (length / 2); ++i)
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{
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char mirrored_char = whole_string[mirrored_index];
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whole_string[mirrored_index] = whole_string[i];
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whole_string[i] = mirrored_char;
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--mirrored_index;
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}
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}
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