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私人定制-词法分析

2024-08-15 07:52:19   221人阅读

私人定制词法分析，能够在输入一整段句子时准确地进行词法分析，并提供种别码表。

通过定义数组循环不断读入与分析单词。

先判断单词是否为数字，如是标志符再进一步判断是关键字、界符还是标识符。

每次读完单词执行一次getchar()后重复循环，当输出##时退出循环。

图片、源代码如下：

#include<stdio.h>#include<string.h>#define Max 100int JdujeNumber(char Words[],int i,int N);int JdujeKeywords(char Words[]);char *table[Max][1]={"#","begin","if","then","while","do","end","l(l|d)*","dd*","+","-","*","/",":",":=","<","<=","<>",">",">=","=",";","(",")"};char Words[Max];main(){    int j,i=0,key;    printf("\n各种单词符号对应的种别码\n");    for(j=0;j<23;j++)    {        printf("%s\t%d\t\t",table[j][0],j);        if(j%2==0)            printf("\n");    }    printf("请输入：（输入##代表结束）");    do    {        scanf("%s",Words);        if(strcmp(Words,"##")==0)        break;        j=JdugeNumber(Words,i,strlen(Words));        if(j==1)            printf("%s\t是数字\n",Words);        else if(j==0)            {                key=JdujeKeywords(Words);                if(key>=0&&key<=7)                {                    printf("%s\t是关键字\n",Words);                }                else if(key>7&&key<=22)                {                    printf("%s\t是界符\n",Words);                }                else                {                    printf("%s\t是标识符\n",Words);                }            }            getchar();    }while(1);    printf("程序结束！");}int JdugeNumber(char Words[],int i,int N){    if(i==N)        return 1;    if(Words[i]>47&&Words[i]<58)    {        JdugeNumber(Words,i+1,N);    }    else        return 0;}int JdujeKeywords(char Words[]){    int i;    for(i=0;i<23;i++)    {        if(strcmp(Words,table[i][1])==0)            return i;    }    return -1;}

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私人定制-词法分析


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