编译原理实验代码

[实验任务]完成以下正则文法所描述的Pascal语言子集单词符号的词法分析程序。

<标识符>→字母︱<标识符>字母︱<标识符>数字<无符号整数>→数字︱<无符号整数>数字<单字符分界符> →+ ︱－︱* ︱; ︱(︱)<双字符分界符>→<大于>=︱<小于>=︱<小于>>︱<冒号>=︱<斜竖>*<小于>→<<等于>→=<大于>→><冒号> →:<斜竖> →/该语言的保留字：begin end if then else for do while and or not 说明：1 该语言大小写不敏感。

2 字母为a-z A-Z，数字为0-9。

3可以对上述文法进行扩充和改造。

4 ‘/*……*/’为程序的注释部分。

[设计要求]1、给出各单词符号的类别编码。

2、词法分析程序应能发现输入串中的错误。

3、词法分析作为单独一遍编写，词法分析结果为二元式序列组成的中间文件。

4、设计两个测试用例（尽可能完备），并给出测试结果。

demo.cpp #include <stdio.h>#include <ctype.h>#include <string.h>#include "demo.h"char token[20];int lookup(char *token) {for (int i = 0; i < 11; i++) {if (strcmp(token, KEY_WORDS[i]) == 0) {return i+1;}}return 0;}char getletter(FILE *fp) {return tolower(fgetc(fp));}void out(FILE *fp, int c, char *value) {fprintf(fp, "%d,%s\n", c, value);}void report_error(FILE *fp, char ch) { fprintf(fp, "There must be some error.\n"); fprintf(fp, "%c...\n", ch);fprintf(fp, "^\n");}void scanner(FILE *infile, FILE *outfile) { char ch;int i, c;do {do {ch = getletter(infile);} while(isspace(ch));if (isalpha(ch)) {token[0] = ch;ch = getletter(infile);i = 1;while (isalnum(ch)) {token[i] = ch;i++;ch = getletter(infile);}token[i] = '\0';fseek(infile, -1, 1);c = lookup(token);if (c == 0) {out(outfile, ID, token);}else {out(outfile, c, " ");}}else {if (isdigit(ch)) {token[0] = ch;ch = getletter(infile);i = 1;while (isdigit(ch)) {token[i] = ch;i++;ch = getletter(infile);token[i] = '\0';fseek(infile, -1, 1);out(outfile, INT, token); }else {switch(ch) {case '<':{ch = getletter(infile);if (ch == '=') {out(outfile, LE, " ");}else if (ch == '>') {out(outfile, NE, " ");}else {fseek(infile, -1, 1);out(outfile, LT, " ");}break;}case '=':{out(outfile, EQ, " ");break;}case '>':{ch = getletter(infile);if (ch == '=') {out(outfile, GE, " ");}else {fseek(infile, -1, 1);out(outfile, GT, " ");}break;}case ':':{ch = getletter(infile);if (ch == '=') {out(outfile, FU, " ");else {fseek(infile, -1, 1);out(outfile, MAO, " "); }break;}case '/':{ch = getletter(infile);if (ch == '*') {out(outfile, ZHU, " "); }else {fseek(infile, -1, 1);out(outfile, XIE, " "); }break;}case '+':{out(outfile, JIA, " "); break;}case '-':{out(outfile, JIAN, " "); break;}case '*':{out(outfile, CHEN, " "); break;}case ';':{out(outfile, FEN, " "); break;}case '(':{out(outfile, ZUO, " "); break;}case ')':{out(outfile, YOU, " ");break;}default:{if (ch != EOF) {report_error(outfile, ch);}break;}}}}} while(ch != EOF);return;}void main() {FILE *in, *out;in = fopen("pascal.txt", "r");out = fopen("result.txt", "w");scanner(in, out);fprintf(out, "0,#");fclose(in);fclose(out);printf("Finished!\n");}本文来自CSDN博客，转载请标明出处：/ffee/archive/2006/05/31/766483.aspx[实验任务]1、实现LL(1)分析中控制程序（表驱动程序）；2、完成以下描述算术表达式的LL(1)文法的LL(1)分析程序（LL(1)分析表见教材）。

E→TE′E′→ATE′|εT→FT′T′→MFT′|εF→(E)|iA→+|-M→*|/说明：终结符号i为用户定义的简单变量,即标识符的定义。

[设计要求]1、输入串应是词法分析的输出二元式序列，即某算术表达式“实验项目一”的输出结果。

输出为输入串是否为该文法定义的算术表达式的判断结果。

2、LL(1)分析过程应能发现输入串出错。

3、设计两个测试用例（尽可能完备，正确和出错），并给出测试结果。

demo.cpp #include <stdio.h>#include <string.h>#include <stdlib.h>#include "demo.h"#define SIZE 100char stack[SIZE];int bottom = 0, top = 0;void push(char ch) {if (top != SIZE) {stack[top] = ch;top++;}}char pop() {if (top != bottom) {top--;stack[top] = '\0';return stack[top];}return -2;}int get_id(FILE *fp) {char temp[100];fscanf(fp, "%d", &id);fgets(temp, 100, fp);return id;}void translate(int id, char *a) {switch(id) {case 0:*a = '#';break;case 12:*a = 'i';break;case 22:*a = '+';break;case 23:*a = '-';break;case 24:*a = '*';break;case 21:*a = '/';break;}}bool is_terminate(char ch) {if (ch == 'i' || ch == '+' || ch == '-' || ch == '*' || ch == '/' || ch == '#') return true;return false;}void trans(char ch, char a, int *i, int *j) {switch (ch) {case 'E':*i = 0;break;case 'e':*i = 1;case 'T':*i = 2; break; case 't':*i = 3; break; case 'F':*i = 4; break; case 'A':*i = 5; break; case 'M': *i = 6; break;}switch (a) { case 'i':*j = 0; break; case '+':*j = 1; break; case '-':*j = 2; break; case '*':*j = 3; break; case '/':*j = 4; break; case '(':*j = 5; break; case ')':*j = 6; break; case '#':*j = 7; break;}}void search_table(char ch, char a) {int i, j;trans(ch, a, &i, &j);char temp[20] = {'\0'};strcpy(temp, TABLE[i][j]);if (strcmp(temp, "~") == 0) {pop();return;}else if (strcmp(temp, "") != 0) {pop();for (unsigned ii = 0; ii < strlen(temp); ii++) { push(temp[ii]);}return;}else {printf("Error!\n");exit(0);}}void main() {FILE *in;int id = 0;char a = 0;in = fopen("result.txt", "r");push('#');push('E');id = get_id(in);translate(id, &a);while (true) {if (is_terminate(stack[top-1])) {if (stack[top-1] == a && a == '#') {printf("success.\n");return;}else if (stack[top-1] == a) {pop();id = get_id(in);translate(id, &a);}else {printf("Error!\n");return;}}else if (!is_terminate(stack[top-1])) {search_table(stack[top-1], a);}}fclose(in);}本文来自CSDN博客，转载请标明出处：/ffee/archive/2006/05/31/766487.aspx[实验任务]完成以下描述算术表达式的LL(1)文法的递归下降分析程序G[E]:E→TE′E′→ATE′|εT→FT′T′→MFT′|εF→(E)|iA→+|-M→*|/说明：终结符号i为用户定义的简单变量,即标识符的定义。