2023年编译原理实验报告.doc

编译原理试验汇报 专 业： 计算机科学与技术 班 级： 1201 学 号： 090915 姓 名： 吴晓阳 指导教师： 张修如 日 期： .12.12 试验一：词法分析 试验目的和规定 设计、编制、调试一种详细的词法分析程序，加深对词法分析原理的理解。 试验描述： 通过对PL/0词法分析程序（GETSYM）的分析，并在此基础上按照附录A中给出的PL/0语言的语法描述，编写一种PL/0语言的词法分析程序。此程序应具有如下功能： 输入为字符串（待进行词法分析的源程序），输出为单词串，即由（单词、类别）所构成的二元组序列。有一定检查错误的能力，例如发现2A此类不能作为单词的字符串。 重要变量名阐明： char *key[8]={"if","else","for","while","do","return","break","continue"}; 确定关键字 char *border[6]={",",";","{","}","(",")"};确定界符 char *arithmetic[4]={"+","-","*","/"};确定算术运算符 char *relation[6]={"<","<=","=",">",">=","<>"};确定关系运算符 程序清单： #include <stdio.h> #include <ctype.h> #include <stdlib.h> #include <string.h> #define NULL 0 #include <iostream> using namespace std; FILE *fp; char cbuffer; char *key[8]={"if","else","for","while","do","return","break","continue"}; char *border[6]={",",";","{","}","(",")"}; char *arithmetic[4]={"+","-","*","/"}; char *relation[6]={"<","<=","=",">",">=","<>"}; char *consts[20]; char *label[20]; int constnum=0,labelnum=0; int search(char searchchar[],int wordtype) { int i=0; switch (wordtype) { case 1:{ for (i=0;i<=7;i++){ if (strcmp(key[i],searchchar)==0) return(i+1); } return 0; } case 2:{ for (i=0;i<=5;i++) { if (strcmp(border[i],searchchar)==0) return(i+1); } return(0); } case 3:{ for (i=0;i<=3;i++) { if (strcmp(arithmetic[i],searchchar)==0){ return(i+1); } } return(0); } case 4:{ for (i=0;i<=5;i++) { if(strcmp(relation[i],searchchar)==0) { return(i+1); } } return(0); } case 5:{ for (i=0;i<=constnum;i++) { if(i!=constnum) { if (strcmp(consts[i],searchchar)==0) return(i+1); } } consts[i-1]=(char *)malloc(sizeof(searchchar));