>#include ‹stream.hxx›
>char v[2][5] = {
> 'a', 'b', 'c', 'd', 'e',
> '0', '1', '2', '3', '4'
>};
>main() {
> for (int i = 0; i‹2; i++) {
> for (int j = 0; j ‹5; j++)
> cout ‹‹ "v[" ‹‹ i ‹‹ "][" ‹‹ j
> ‹‹ "]=" ‹‹ chr(v[i][j]) ‹‹ " ";
> cout ‹‹ "\n";
> }
>}
>#include ‹stream.hxx›
>struct pair {
> char* name;
> int val;
>};
>extern int strlen(char*);
>extern int strcpy(char*, char*);
>extern int strcmp(char*, char*);
>const large = 1024;
>static pair vec[large];
>pair* find(char* p)
>{
> for (int i=0; vec[i].name; i++)
> if (strcmp(p,vec[i].name)==0) return &vec[i];
> if (i == large) return &vec[large-1];
> return &vec[i];
>}
>int& value(char* p)
>{
> pair* res = find(p);
> if (res-›name == 0) {
> res-›name = new char[strlen(p)+1];
> strcpy(res-›name,p);
> res-›val = 0;
> }
> return res-›val;
>}
>const MAX = 256;
>main ()
>{
> char buf [MAX];
> while (cin››buf) value(buf)++;
> for (int i=0; vec[i].name; i++)
> cout ‹‹ vec[i].name ‹‹ ":" ‹‹ vec[i].val ‹‹ "\n";
>}
>#include ‹xstream.hxx›
>#include ‹ctype.h›
>enum token_value {
> NAME, NUMBER, END,
> PLUS = '+', MINUS = '-', MUL='*', DIV='/',
> PRINT=';', ASSIGN='=', LP='(', RP=')'
>};
>token_value curr_tok;
>struct name {
> char* string;
> name* next;
> double value;
>};
>const TBLSZ = 23;
>name* table[TBLSZ];
>int no_of_errors;
>double error(char* s) {
> cerr ‹‹ "error: " ‹‹ s ‹‹ "\n";
> no_of_errors++;
> return 1;
>}
>extern int strlen(const char*);
>extern int strcmp(const char*, const char*);
>extern char* strcpy(char*, const char*);
>name* look(char* p, int ins = 0)
>{
> int ii= 0;
> char *pp = p;
> while (*pp) ii = ii‹‹1 ^ *pp++;
> if (ii ‹ 0) ii = -ii;
> ii %= TBLSZ;
> for (name* n=table [ii]; n; n=n-›next)
> if (strcmp(p,n-›string) == 0) return n;
> if (ins == 0) error("name not found");
> name* nn = new name;
> nn-›string = new char[strlen(p) + 1];
> strcpy(nn-›string,p);
> nn-›value = 1;
> nn-›next = table[ii];
> table[ii] = nn;
> return nn;
>}
>inline name* insert(char* s) { return look (s,1); }
>token_value get_token();
>double term();
>double expr()
>{
> double left = term();
> for (;;)
> switch (curr_tok) {
> case PLUS:
> get_token();
> left += term();
> break;
> case MINUS:
> get_token();
> left -= term();
> break;
> default:
> return left;
> }
>}
>double prim();
>double term()
>{
> double left = prim();
> for (;;)
> switch (curr_tok) {
> case MUL:
> get_token();
> left *= prim();
> break;
> case DIV:
> get_token();
> double d = prim();
> if (d == 0) return error("divide by 0");
> left /= d;
> break;
> default:
> return left;
> }
>}
>int number_value;
>char name_string[80];
>double prim()
>{
> switch (curr_tok) {
> case NUMBER:
> get_token();
> return number_value;
> case NAME:
> if (get_token() == ASSIGN) {
> name* n = insert(name_string);
> get_token();
> n-›value = expr();
> return n-›value;
> }
> return look(name_string)-›value;
> case MINUS:
> get_token();
> return -prim();
> case LP:
> get_token();
> double e = expr();
> if (curr_tok != RP) return error(") expected");
> get_token();
> return e;
> case END:
> return 1;
> default:
> return error ("primary expected");
> }
>}
>token_value get_token()
>{
> char ch = 0;
> do {
> if (!cin.get(ch)) return curr_tok = END;
> } while (ch !='\n' && isspace(ch));
> switch (ch) {
> case ';':
> case '\n':
> cin ›› WS;
> return curr_tok=PRINT;
> case '*':
> case '/':
> case '+':
> case '-':
> case '(':
> case ')':
> case '=':
> return curr_tok=ch;
> case '0': case '1': case '2': case '3': case '4':
> case '5': case '6': case '7': case '8': case '9':
> case '.':
> cin.putback(ch);
> cin ›› number_value;
> return curr_tok=NUMBER;
> default:
> if (isalpha(ch)) {
> char* p = name_string;
> *p++ = ch;
> while (cin.get(ch) && isalnum(ch)) *p++ = ch;
> cin.putback(ch);
> *p = 0;
> return curr_tok=NAME;
> }
> error ("bad token");
> return curr_tok=PRINT;
> }
>}
>int main(int argc, char* argv[])
>{
> switch (argc) {
> case 1:
> break;
> case 2:
> cin = *new istream(strlen(argv[1]),argv[1]);
> break;
> default:
> error("too many arguments");
> return 1;
