《编译原理》课程实验报告实验题目：某种简单程序语言的词法分析器的设计与实现专业：计算机科学与技术班级：11060341学号：11060341姓名：实验目的：设计一个词法分析程序，理解词法分析器实现的原理，掌握程序设计语言中的各类单词的词法分析方法，加深对词法分析原理的理解。

实验任务：词法分析是从左向右扫描每行源程序的符号，拼成单词，换成统一的二元式(单词种别，单词符号的属性值)表示。

对给定的程序通过词法分析器识别一个个单词符号，并以二元式(单词种别，单词符号的属性值)显示，本程序则是通过对给定程序段分析后以单词符号和文字提示显示）实验流程：程序清单：#include<iostream>#include<cstdio>#include<cstring>using namespace std;int k=0;struct word{char name[10];int kind;} word[1000];char key[35][10]= {"scanf","short","int","long","float","double","char","struct","union","printf","typedef","const","unsigned","signed","extern","register","static","volatile","void","if","else","switch","case","for","do","while","goto","continue","break","default","sizeof","return","include","bool"};bool cmp(char a[]){int i;for(int k=0; k<35; k++){if(strcmp(a,key[k])==0)return 1;}return 0;}int main(){#ifdef LOCALfreopen("in.txt", "r", stdin);freopen("out.txt", "w", stdout);#endifint p,q,flag;char a[1000],b[10],ch;while(gets(a)){p=0;int len=strlen(a);while(p<len){ch=a[p];memset(b,0,sizeof(b));while(ch==' '){p++;ch=a[p];}if((ch>='a'&&ch<='z')||(ch>='A'&&ch<='Z')||ch=='_'){flag=0;q=0;while((ch>='a'&&ch<='z')||(ch>='A'&&ch<='Z')||ch=='_'||(ch>='0'&&ch<='9')) {if((ch>='0'&&ch<='9')||ch=='_')flag=1;b[q++]=ch;p++;ch=a[p];}if(flag==1){strcpy(word[k].name,b);word[k++].kind=1;}else if(flag==0){if(ch=='\''||ch=='"'){strcpy(word[k].name,b);word[k++].kind=2;}else if(cmp(b)==1){strcpy(word[k].name,b);word[k++].kind=3;}else{strcpy(word[k].name,b);word[k++].kind=1;}}}else if((ch>='0'&&ch<='9')||ch=='-'){if(a[t]>='0'&&a[t]<='9'||a[t]>='a'&&a[t]<='z'||a[t]>='A'&&a[t]<='Z'){p++;ch=a[p];if(ch=='-'||ch=='='){b[0]='-';b[1]=ch;strcpy(word[k].name,b);word[k++].kind=5;ch=a[++p];}else{b[0]='-';strcpy(word[k].name,b);word[k++].kind=5;}}else{q=0;b[q++]=ch;p++;ch=a[p];while((ch>='0'&&ch<='9')||ch=='.'){b[q++]=ch;p++;ch=a[p];}strcpy(word[k].name,b);word[k++].kind=2;}}elseif(ch=='('||ch==')'||ch=='['||ch==']'||ch=='{'||ch=='}'||ch==','||ch==';'||ch==':'||ch=='\''||ch=='"')//ch=='('| |ch==')'||ch=='['||ch==']'||ch=='{'||ch=='}'||{b[0]=ch;strcpy(word[k].name,b);word[k++].kind=4;}else if(ch=='%'||ch=='^'){b[0]=ch;strcpy(word[k].name,b);word[k++].kind=5;ch=a[++p];}else if(ch=='+'){p++;ch=a[p];if(ch=='+'||ch=='='){b[0]='+';b[1]=ch;strcpy(word[k].name,b);word[k++].kind=5;ch=a[++p];}else{b[0]='+';strcpy(word[k].name,b);word[k++].kind=5;}}else if(ch=='*'){p++;ch=a[p];if(ch=='*'||ch=='='){b[0]='*';b[1]=ch;strcpy(word[k].name,b);word[k++].kind=5;ch=a[++p];}else{b[0]='*';strcpy(word[k].name,b);word[k++].kind=5;}}else if(ch=='/'){p++;ch=a[p];if(ch=='/'||ch=='='){b[0]='/';b[1]=ch;strcpy(word[k].name,b);word[k++].kind=5;ch=a[++p];}else{b[0]='/';strcpy(word[k].name,b);word[k++].kind=5;}}else if(ch=='='){p++;ch=a[p];if(ch=='='){b[0]=b[1]='=';strcpy(word[k].name,b);word[k++].kind=5;ch=a[++p];}else{b[0]='=';strcpy(word[k].name,b);word[k++].kind=5;}}else if(ch=='>'){p++;ch=a[p];if(ch=='>'||ch=='='){b[0]='>';b[1]=ch;strcpy(word[k].name,b);word[k++].kind=5;ch=a[++p];}else{b[0]='>';strcpy(word[k].name,b);word[k++].kind=5;}}else if(ch=='<'){p++;ch=a[p];if(ch=='<'||ch=='='){b[0]='<';b[1]=ch;strcpy(word[k].name,b);word[k++].kind=5;ch=a[++p];}else{b[0]='<';strcpy(word[k].name,b);word[k++].kind=5;}}else if(ch=='!'){p++;ch=a[p];if(ch=='='){b[0]='!';b[1]='=';strcpy(word[k].name,b);word[k++].kind=5;ch=a[++p];}else{b[0]='!';strcpy(word[k].name,b);word[k++].kind=5;}}else if(ch=='&'){p++;ch=a[p];if(ch=='&'){b[0]=b[1]='&';strcpy(word[k].name,b);word[k++].kind=5;ch=a[++p];}else{b[0]='&';strcpy(word[k].name,b);word[k++].kind=5;}}else if(ch=='|'){p++;ch=a[p];if(ch=='|'){b[0]=b[1]='|';strcpy(word[k].name,b);word[k++].kind=5;ch=a[++p];}else{b[0]='|';strcpy(word[k].name,b);word[k++].kind=5;}}}}for(int i=0; i<k; i++){switch(word[i].kind){case 1:{printf("(标识符,");break;}case 2:{printf("(常量,");break;}case 3:{printf("(关键字,");break;}case 4:{printf("(界符,");break;}case 5:{printf("(运算符,");break;}}printf("%s)\n",word[i].name); }int a1=0,a2=0,a3=0,a4=0,a5=0; for(int i=0;i<k;i++){if(word[i].kind==1)a1++;else if(word[i].kind==2)a2++;else if(word[i].kind==3)a3++;else if(word[i].kind==4)a4++;else if(word[i].kind==5)a5++;}printf("标识符：%d\n常量：%d\n关键字：%d\n界符：%d\n运算符：%d\n",a1,a2,a3,a4,a5);return 0;}运行结果：。