编译原理实验报告
编译原理实验报告
Compilers Principles Experiment Report
所在学院：
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2015 年 12 月
词法分析程序
一、实验目的：
设计、编制和调试一个具体的词法分析程序，加深对词法分析的理解。
二、实验要求：
1、通过对 PL/0 词法分析程序(GETSYS)的分析，编制一个具有以下功能的词法分析程序：
a.输入为字符串（或待进行词法分析的源程序），输出为单词串，即由（单词，类别）所组成的二元组序列；
b.有一定的错误检查能力，例如能发现 2a这类
不能作为单词的字符串。
三、实验代 码
#define ID 12//标识符
#define INT 13//常数
#define JF 14//界符
#define YSF 15//运算符
#define N 30//字符读取的最大长度
char TOKEN[N];
FILE *write;
//查询一个字符串，看其是否与指定的字符相匹配，如果匹配返回 1 个非零的值，如果不匹配，则返回一个 0 值*/
int looksame(char *a)
{
int i;
char*key[22] = { "begin","end","if","then","else","for","do","while","and","or","not","BEGIN","END","IF","THEN","ELSE","FOR","DO","WHILE","AND","OR","NOT" };
for (i = 0;i < 22;i++)
{
if (strcmp(key[i], a) == 0)//该字符串是否与关键字相匹配
return (i % 11 + 1);
}
return 0;
}
//把 a输入到指定文件中，然后从该文件中读出字符串，放到一个数组中输出
void out(int a, char *b)
{
FILE *write;
write = fopen("E:\\b.txt", "a+");
if (write == NULL)
{
printf("文件打开失败");
exit(0);
}
fprintf(write, "%d\t", a);
fwrite(b, strlen(b), 1, write);
fprintf(write, "\n");
fclose(write);
printf("%d %20s\t\t", a, b);
}
int error()
{
printf("书写格式错误，未被识别\n");
return 0;
}
void function(FILE *fp)
{
char ch = " ";
int i, c;
while (ch != EOF)
{
ch = fgetc(fp);//从文件中读取字符
while (ch == " " || ch == "\t" || ch == "\n") {
ch = fgetc(fp);
}
if (isalpha(ch)) //isalpha()判断是否为英文字母，是则返回非
零值，否则返回零
{
TOKEN[0] = ch;
ch = fgetc(fp);
i = 1;
while (isalnum(ch))
//isalnum()判断字符是否为英文字
母或数字,如果是则返回非零值，如果不是则返回零//
{
TOKEN[i] = ch;
i++;
ch = fgetc(fp);
}
TOKEN[i] = "\0";
fseek(fp, -1, 1);
//用于二进制方式打开的文件,移动文件读写指针位置
c = looksame(TOKEN);
if (c == 0)
{
out(ID, TOKEN);printf("标识符\n");
}
else
{
out(c, TOKEN);printf("关键字\n");
}
}
else if (isdigit(ch))
//isdigit()判断是否为0-9 的数字
{
TOKEN[0] = ch;
ch = fgetc(fp);
i = 1;
while (isdigit(ch))
{
TOKEN[i] = ch;
i++;
ch = fgetc(fp);
}
TOKEN[i] = "\0";
fseek(fp, -1, 1);
out(INT, TOKEN);
printf("常数\n");
}
else
{
switch (ch)
{
case"+":out(YSF, "+");printf("运算符\n");
break;
case"-":out(YSF, "-");printf("运算符\n");
break;
case";":out(JF, ";");printf("界符\n");
break;
case",":out(JF, ",");printf("界符\n");
break;
case"|":out(YSF, "|");printf("运算符\n");
break;
case"{":out(JF, "{");printf("界符\n");
break;
case"(":out(JF, "(");printf("界符\n");
break;
case"!":out(JF, "!");printf("界符\n");
break;
case"^":out(JF, "^");printf("界符\n");
break;
case")":out(JF, ")");printf("界符\n");
break;
case"}":out(JF, "}");printf("界符\n");
break;
case"<":ch = fgetc(fp);
if (ch == "=")
{
out(YSF, "<=");
printf("运算符\n");
}
else if (ch == ">")
{
out(YSF, "<>");
printf("运算符\n");
}
else
{
fseek(fp, -1, 1);
out(YSF, "<");
printf("运算符\n");
}
break;
case"=":out(YSF, "=");printf("运算符\n");
break;
case">":ch = fgetc(fp);
if (ch == "=")
{
out(YSF, ">=");
printf("运算符\n");
}
else
{
fseek(fp, -1, 1);
out(YSF, ">");
printf("运算符\n");
}
break;
case":":ch = fgetc(fp);
if (ch == "=")
{
out(YSF, ":=");
printf("运算符\n");
}
else
{
fseek(fp, -1, 1);
out(JF, ":");
printf("界符\n");
}
break;
case"/":ch = fgetc(fp);
if (ch == "*")
{
out(JF, "/*");
printf("界符\n");
while (1)//注释的内容在词法分析中不显示
while (ch != "/")
ch = fgetc(fp);
fseek(fp, -2, 1);
ch = fgetc(fp);
if (ch == "*")
{
fseek(fp, 1, 1);
break;
}
else
{
fseek(fp, 2, 1);
ch = fgetc(fp);
}
fseek(fp, -2, 1);
}
else
{
fseek(fp, -1, 1);
out(JF, "/");
printf("界符\n");
}
break;
case"*":ch = fgetc(fp);
if (ch == "/")
{
out(JF, "*/");
printf("界符\n");
}
else
{
fseek(fp, -1, 1);
out(YSF, "*");
printf("运算符\n");
}
break;
case EOF:break;
default:error();
break;
}
}
}
}
int main()
{
FILE *read;
read = fopen("E:\\a.txt", "r");
write = fopen("E:\\b.txt", "a+");
if (read == NULL)
{
printf("FILE OPEN FAIL!");
exit(0);
}
printf("===========================================================\n");
printf("====================词法分析程序===========================\n");
printf("===========该分析程序的文件存放在E：\\a.txt 目录下==========\n");
printf("===========该程序的分析结果存放在E：\\b.txt 目录下===========\n");
printf("===============================
=============================\n");
function(read);
fclose(read);
system("pause");
return 0;
}
四、实验截图
a.txt
b.txt
基于 LL(1)方法的语法分析程序
一、 实验目的
设计、编制和调试一个典型的语法分析方法，进一步掌握常用的语法分析方法。
二、实验要求
1、根据 LL(1)分析法编写一个语法分析程序，可根据自己实际情况，选择以下一项作为分析算法的输入：
a.直接输入根据已知文法构造的分析表 M;
b.输入文法的 FIRST(α)和 FOLLOW(U)集合，由
程序自动生成文法的分析表 M；
c.输入已知文法，由程序自动构造文法的分析表M。
2、程序具有通用性
所开发的程序可适用于不同的文法和任意输入串，且能判断该文法是否为 LL(1)文法。
3、有运行实例
对于输入的文法和符号串，所编制的语法分析程序应能正确判断此串是否为文法的句子，并要求输出分析过程。
三、实验代码
#include "stdafx.h"
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<dos.h>
char A[20];/*分析栈*/
char B[20];/*剩余串*/
char v1[20] = { "i","+","*","(",")","#" };/*终结符
*/
char v2[20] = { "E","G","T","S","F" };/*非终结符
*/
int j = 0, b = 0, top = 0, l;/*L 为输入串长度 */
typedef struct type
/*产生式类型定义
*/
{
char origin; /*大写字符
*/
char array[5]; /*产生式右边字符 */
int length; /*字符个数
*/
}type;
type e, t, g, g1, s, s1, f, f1;/*结构体变量
*/
type C[10][10];/*预测分析表
*/
void print()/*输出分析栈
*/
{
int a;/*指针*/
for (a = 0;a <= top + 1;a++)
printf("%c", A[a]);
printf("\t\t");
}/*print*/
void print1()/*输出剩余串*/
{
int j;
for (j = 0;j<b;j++)/*输出对齐符*/
printf(" ");
for (j = b;j <= l;j++)
printf("%c", B[j]);
printf("\t\t\t");
}
int _tmain(int argc, _TCHAR* argv[])
{
int m, n, k = 0, flag = 0, finish = 0;
char ch, x;
type cha;/*用来接受 C[m][n]*/
/*把文法产生式赋值结构体*/
e.origin = "E";
strcpy(e.array, "TG");
e.length = 2;
t.origin = "T";
strcpy(t.array, "FS");
t.length = 2;
g.origin = "G";
strcpy(g.array, "+TG");
g.length = 3;
g1.origin = "G";
g1.array[0] = "^";
g1.length = 1;
s.origin = "S";
strcpy(s.array, "*FS");
s.length = 3;
s1.origin = "S";
s1.array[0] = "^";
s1.length = 1;
f.origin = "F";
strcpy(f.array, "(E)");
f.length = 3;
f1.origin = "F";
f1.array[0] = "i";
f1.length = 1;
for (m = 0;m <= 4;m++)/*初始化分析表*/
for (n = 0;n <= 5;n++)
C[m][n].origin = "N";/*全部赋为空*/
/*填充分析表*/
C[0][0] = e;C[0][3] = e;
C[1][1] = g;C[1][4] = g1;C[1][5] = g1;
C[2][0] = t;C[2][3] = t;
C[3][1] = s1;C[3][2] = s;C[3][4] = C[3][5] = s1;
C[4][0] = f1;C[4][3] = f;
printf("提示:本程序只能对由"i","+","*","(",")"构成的
以"#"结束的字符串进行分析,\n");
printf("请输入要分析的字符串:");
do/*读入分析串*/
{
scanf("%c", &ch);
if ((ch != "i") && (ch != "+") && (ch != "*") && (ch != "(") && (ch != ")") && (ch != "#"))
{
printf("输入串中有非法字符\n");
exit(1);
}
B[j] = ch;
j++;
} while (ch != "#");
l = j;/*分析串长度*/
ch = B[0];/*当前分析字符*/
A[top] = "#"; A[++top] = "E";/*"#","E"进栈*/
printf("步骤\t\t 分析栈 \t\t 剩余字符 \t\t 所用产生式 \n");
do
{
x = A[top--];/*x 为当前栈顶字符*/
printf("%d", k++);
printf("\t\t");
for (j = 0;j <= 5;j++)/*判断是否为终结符*/
if (x == v1[j])
{
flag = 1;
break;
}
if (flag == 1)/*如果是终结符*/
{
if (x == "#")
{
finish = 1;/*结束标记*/
printf("acc!\n");/*接受 */
getchar();
getchar();
exit(1);
}/*if*/
if (x == ch)
{
print();
print1();
printf("%c匹配\n", ch);
ch = B[++b];/*下一个输入字符*/
flag = 0;/*恢复标记*/
}/*if*/
else/*出错处理*/
{
print();
print1();
printf("%c出错\n", ch);/*输出出错终结符*/
exit(1);
}/*else*/
}/*if*/
else/*非终结符处理*/
{
for (j = 0;j <= 4;j++)
if (x == v2[j])
{
m = j;/*行号*/
break;
}
for (j = 0;j <= 5;j++)
if (ch == v1[j])
{
n = j;/*列号*/
break;
}
cha = C[m][n];
if (cha.origin != "N")/*判断是否为空*/
{
print();
print1();
printf("%c->", cha.origin);/*输出产生式*/
for (j = 0;j<cha.length;j++)
printf("%c", cha.array[j]);
printf("\n");
for (j = (cha.length - 1);j >= 0;j--)/*产生式逆序入栈*/
A[++top] = cha.array[j];
if (A[top] == "^")/*为空则不进栈*/
top--;
}/*if*/
else/*出错处理*/
{
print();
print1();
printf("%c出错\n", x);/*输出出错非终结符*/
exit(1);
}/*else*/
}/*else*/
} while (finish == 0);
return 0;
}
四、 实验截图
于 基于 LR(0) 方法的语法分析程序
一、实验目的
设计、编制和调试一个典型的语法分析方法，进一步掌握常用的语法分析方法。
二、实验要求
可根据自己实际情况，选择以下一项作为分析算法的输入：
（1）直接输入根据己知文法构造的 LR(0)分析表。
（2）输入已知文法的项目集规范族和转换函数，由程序自动生成 LR(0)分析表； （3）输入已知文法，由程序自动生成 LR(0)分析表。
三、程序代码
#include "stdafx.h"
#include<iostream>
#include<string.h>
#include<iomanip>
#include<stdlib.h>
using namespace std;
struct stack {
int
top;
int
st[15];
//状态栈
char sn[15];
//符号栈
}*sign;
struct analysis {
//动作表结构
char act;
int
status;
}action[][6] = {
{
"s",5,"$",0,"$",0, "s",4,"$",0, "$",0
},
{
"$",0,"s",6,"$",0, "$",0,"$",0, "A",0
},
{
"$",0,"r",2,"s",7, "$",0,"r",2, "r",2
},
{
"$",0,"r",4,"r",4, "$",0,"r",4, "r",4
},
{
"s",5,"$",0,"$",0, "s",4,"$",0, "$",0
},
{
"$",0,"r",6,"r",6, "$",0,"r",6, "r",6
},
{
"s",5,"$",0,"$",0, "s",4,"$",0, "$",0
},
{
"s",5,"$",0,"$",0, "s",4,"$",0, "$",0
},
{
"$",0,"s",6,"$",0, "$",0,"s",11,"$",0
},
{
"$",0,"r",1,"s",7, "$",0,"r",1, "r",1
},
{
"$",0,"r",3,"r",3, "$",0,"r",3, "r",3
},
{
"$",0,"r",5,"r",5, "$",0,"r",5, "r",5
}
};
analysis G[] = {
{
"E",3
},{
"E",1
},{
"T",3
},{
"T",1
},{
"F",3
},{
"F",1
}
};
//此文法信息
int go[][3] = {
1,2,3,99,99,99,99,99,99,99,99,99,8,2,3,99,99,99,99,9,3,99,99,10,99,99,99,99,99,99,99,99,99,99,99,99
};
int index(char m) {
int id;
if ((m == "i") || (m == "E"))
id = 0;
else if ((m == "+") || (m == "T"))
id = 1;
else if ((m == "*") || (m == "F"))
id = 2;
else if (m == "(")
id = 3;
else if (m == ")")
id = 4;
else if (m == "#")
id = 5;
else
id = 99;
return id;
}
void main() {
cout << "参照文法为:\n" << "(1)E→E+T\n" << "(2)E→T\n" << "(3)T→T*F"\n"\
<< "(4)T→F\n" << "(5)F→(E)\n" << "(6)F→i\n";
char instr[20], *current, a;
int i = 0, step = 0, ix1, ia, ix2, ig, iG, back;
bool flag = true;
sign = new stack;
cout << "请输入待分析的字符串(以#结束):\n";
do {
cin >> instr[i++];
} while (instr[i - 1] != "#");
instr[i] = "\0";
current = instr;
sign->st[0] = 0;sign->sn[0] = "#";sign->sn[1] = "\0";sign->top = 0;
cout << "步骤" << setw(20) << "状
态" << setw(20) << "符
号" << setw(20) << "输 入 串\n";
cout << "====" << setw(20) << "======" << setw(20) << "======" << setw(20) << "========\n";
cout << step++ << setw(20) << sign->st[0] << setw(21) << sign->sn << setw(21) << instr << endl;
while (flag) {
cout << step++ << setw(20);
a = *current;ia = index(a);
ix1 = sign->st[sign->top]; //cout<<a<<" "<<ia<<" "<<ix1<<" "<<action[ix1][ia].act;
//hhjhj
if (ia == 99) {
cout << "此文法无法识别该输入串!";
break;
}
if (action[ix1][ia].act == "s") {
sign->top += 1;
sign->sn[sign->top] = a;
sign->sn[(sign->top) + 1] = "\0";
sign->st[sign->top] = action[ix1][ia].status;
current++;
}
else if (action[ix1][ia].act == "r") {
iG = action[ix1][ia].status - 1;
//零下表开始
back = G[iG].status;
sign->top -= back;
ix2 = sign->st[sign->top];
ig = index(G[iG].act);
if (go[ix2][ig] != 99)
sign->top += 1;
sign->st[sign->top] = go[ix2][ig];
sign->sn[sign->top] = G[iG].act;
sign->sn[(sign->top) + 1] = "\0";
}
else {
cout << "此文法无法识别该输入串!";
break;
}
}
else if (action[ix1][ia].act == "$") {
cout << "此文法无法识别该输入串!";
break;
}
else if (action[ix1][ia].act == "A") {
flag = false;
}
for (i = 0;i <= sign->top;i++)
cout << sign->st[i] << " ";
cout << setw(20 - (sign->top)) << sign->sn << setw(20 - strlen(sign->sn)) << current << endl;
if (flag == false)
cout << "文法分析成功!" << endl;
}
}
四、实验截图
中间代码生成程序（逆波兰表示）
一、实验目的
加深对语义翻译的理解
二、实验要求
（1）编制一个中间代码生成程序，能将算术表达式等翻译成逆波兰形式； （2）程序具有通用性，即能接受各种不同的算术表达式等语法成分。
（3）有运行实例．对于语法正确的算术表达式，能生成逆波兰表示，并输出结果；对不正确的表达式，能检测出错误。
(4)
提交实习报告，报告内容应包括：
目的、要求，算法描述，程序代码，运行截图 三、程序代码
#include "stdafx.h"
#include <iostream>
#include <string>
using namespace std;
class Transform
{
private:
char s_stack[20];//栈
string s_result;//转换之后的字符串，也就是后缀表达式
int top;//栈顶
public:
Transform()
{
top=0;
s_stack[0]="#";
s_result="";
}
void pop()
{
top--;
}
void push(char b)
{
top++;
s_stack[top]=b;
}
string TF(string a)
{
bool q=0;
for (int i=0;i<a.length();i++)
{
switch (a[i])
{
case "+":
case "-":
q=1;
if (s_stack[top]!="*"&&s_stack[top]!="/"&&s_stack[top]!="@"&&s_stack[top]!="+"&&s_stack[top]!="-")
{
push(a[i]);
}
else
{
while(s_stack[top]=="*"||s_stack[top]=="/"||s_stack[top]=="@"||s_stack[top]=="+"||s_stack[top]=="-")
{
s_result+=s_stack[top];
pop();
}
push(a[i]);
}
break;
case "*":
case "/":
q=1;
if (s_stack[top]!="@"&&s_stack[top]!="*"&&s_stack[top]!="/")
{
push(a[i]);
}
else
{
while(s_stack[top]=="@"||s_stack[top]=="*"||s_stack[top]=="/")
{
s_result+=s_stack[top];
pop();
}
push(a[i]);
}
break;
case ":=":
q=1;
if (s_stack[top]!="*"&&s_stack[top]!="/"&&s_stack[top]!="@"&&s_stack[top]!="+"&&s_stack[top]!="-")
{
push(a[i]);
}
else
{
while(s_stack[top]=="*"||s_stack[top]=="/"||s_stack[top]=="@"||s_stack[top]=="+"||s_stack[top]=="-")
{
s_result+=s_stack[top];
pop();
}
push(a[i]);
}
break;
case "@"://负号
q=1;
if (s_stack[top]!="@")
{
push(a[i]);
}
else
{
while(s_stack[top]=="@")
{
s_result+=s_stack[top];
pop();
}
push(a[i]);
}
break;
case "(":
q=1;
push(a[i]);
break;
case ")":
q=1;
while(s_stack[top]!="(")
{
s_result+=s_stack[top];
pop();
}
pop();//遇到第一个匹配的（
while(s_stack[top]!="(")//可能有第二、三、四、、、、个（，
如果有，遇到会停
{
if(s_stack[top]=="#")break;
s_result+=s_stack[top];
pop();
}
break;
}
if (q==0)
{
s_result+=a[i];
}
else
{
q=0;
}
}
while(s_stack[top]!="#")//把栈中的字符都出栈
{
s_result+=s_stack[top];
pop();
}
s_result+=s_stack[top];//末尾加上#
return s_result;
}
};
void main()
{
cout<<"请输入表达式（取反用@表示,以#结束）";
string s_in;
string s_out;
cin>>s_in;
Transform T;
s_out=T.TF(s_in);
cout<<"逆波兰表达式为："<<s_out<<endl;
system("pause");
}
四、实验截图
封面设计：
贾丽
地 址：中国河北省秦皇岛市河北大街 438 号
邮 编：066004
电 话：0335-8057068
传 真：0335-8057068
网 址：http://jwc.ysu.edu.cn
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