实现去除c语言注释的小工具

去除C代码中的注释，
1. 单行注释//；
2. 多行注释/**/；
3. 单行注释以“\”结尾则下一行也为注释；
4. 字符串中的注释不处理。
说是C语言，但其实所有C语系的都可以，比如Java。

小工具：去除C语言注释 

int main(int argc, char* argv[]) {
  enum {
    literal,
    single,
    multiple,
    string
  } mode = literal;
  char last = 0, current;

  while ((current = getchar()) != EOF) {
    switch (mode) {
    case single: {
      if (last != '\\' && (current == '\n' || current == '\r')) {
        putchar(current);
        current = 0;
        mode = literal;
      }
    } break;
    case multiple: {
      if (last == '*' && current == '/') {
        current = 0;
        mode = literal;
      }
    } break;
    case string: {
      if (last == '\\') {
        putchar(last);
        putchar(current);
      } else if (current != '\\') {
        putchar(current);
        if (current == '"') {
          mode = literal;
        }
      }
    } break;
    default: {
      if (last == '/') {
        if (current == '/') {
          mode = single;
        } else if (current == '*') {
          mode = multiple;
        } else {
          putchar(last);
          putchar(current);
        }
      } else if (current != '/') {
        putchar(current);
        if (current == '"') {
          mode = string;
        }
      }
    } break;
    }
    last = current;
  }

  return 0;
}
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测试代码

int main (int argc, char *argv[])
{
// not show\
not show\
not show
// not show
/* not show */
    int is; // not show
    int/* not show */ ms; /* not show */
    double ds; // not show\
    not show\
    not show
    double dm; /* ...
    not show
    not show */ float fs; /**
                           * now show
                           */
    float/**/ fm;
    char cs[] = "aaa // /***/";
    char cm1[] = /* not show */"hello*/";
    char cm2[] = "/*redraiment"/* not show */;
    /* printf("/////"); */
    return EXIT_SUCCESS;
}
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处理后的代码

int main (int argc, char *argv[])
{

    int is;
    int ms;
    double ds;
    double dm;  float fs;
    float fm;
    char cs[] = "aaa // /***/";
    char cm1[] = "hello*/";
    char cm2[] = "/*redraiment";

    return EXIT_SUCCESS;
}
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