VS2010环境在一个程序中实现语法分析和词法分析,求代码

发布网友发布时间：2022-05-13 19:40

共1个回答

热心网友时间：2023-10-23 13:33

//一个词法分析程序，输入源程序，输出二元组（词法记号 , 属性值 / 其在符号表中的位置）构成的序列

#include<iostream>
#include<cstring>
using namespace std;

//char * keywords[6] = {"for","if","then","else","while","do" };

int zimu(char a)//分析是否为字母
{
    if ((a>='a')&&(a<='z'))
        return 1;
    else
        return 0;
}

int shuzi(char a)
{
    if ((a>='0')&&(a<='9'))
        return 1;
    else
        return 0;
}

int biaodian(char a)
{
    if(!zimu(a) && !shuzi(a))
        return 1;
    else
        return 0;
}

void showstring(char * a)
{
    int count = 0;
    while( a[count]!='\0')
        cout<<a[count++];
}

void fenxi()
{
    char * sentence;
    sentence = new char[50];//储存输入的句子
    int i = 0;
    char input;
    while(cin>>input && input!='#' && i<50)
    {
        sentence[i] = input;
        i++;
    }

    char ** id;
    id = new char*[20];
    for(int m = 0;m<20;m++)
    {
        id[m] = new char[10];
    }
    for(int x = 0;x<20;x++)
    {
        for(int y = 0;y<10;y++)
            id[x][y] = '\0';
    }

    char ** num;
    num = new char*[20];
    for( m = 0;m<20;m++)
    {
        num[m] = new char[10];
    }
    for( x = 0;x<20;x++)
    {
        for(int y = 0;y<10;y++)
            num[x][y] = '\0';
    }

    int * token;
    token  = new int[30];
    int t = 0;//标记token中的词法记号个数

    int danci = -1;//记录字母串的单词个数
    int shuzichuan = -1;
    int dancilong = 0;//记录单词中字母个数

    int k = 0;//记录sentence 中的遍历数位
    for(k = 0;k<i;)
    {
        if(zimu(sentence[k]))
        {
            danci ++;
            id[danci][dancilong] = sentence[k];
            k++;
            while(!biaodian(sentence[k]) && k<i)
            {
                dancilong++;
                id[danci][dancilong] = sentence[k];
                k++;
            }
            dancilong = 0;
            if(strcmp("for",id[danci]) ==0)
            {
                token[t] = 1;
            }
            if(strcmp("if",id[danci]) ==0)
            {
                token[t] = 2;
            }
            if(strcmp("then",id[danci]) ==0)
            {
                token[t] = 3;
            }
            if(strcmp("else",id[danci]) ==0)
            {
                token[t] = 4;
            }
            if(strcmp("while",id[danci]) ==0)
            {
                token[t] = 5;
            }
            if(strcmp("do",id[danci]) ==0)
            {
                token[t] = 6;
            }
            else
                token[t] = 10;
            t++;
        }

        if(biaodian(sentence[k]))
        {
            danci ++;
            id[danci][dancilong] = sentence[k];
            k++;
            while(biaodian(sentence[k]) && k<i)
            {
                dancilong++;
                id[danci][dancilong] = sentence[k];
                k++;
            }
            dancilong = 0;
            if(strcmp("+",id[danci]) ==0)
            {
                token[t] = 13;
            }
            if(strcmp("-",id[danci]) ==0)
            {
                token[t] = 14;
            }
            if(strcmp("*",id[danci]) ==0)
            {
                token[t] = 15;
            }
            if(strcmp("/",id[danci]) ==0)
            {
                token[t] = 16;
            }
            if(strcmp(":",id[danci]) ==0)
            {
                token[t] = 17;
            }
            if(strcmp(":=",id[danci]) ==0)
            {
                token[t] = 18;
            }
            if(strcmp("<",id[danci]) ==0)
            {
                token[t] = 20;
            }
            if(strcmp("<>",id[danci]) ==0)
            {
                token[t] = 21;
            }
            if(strcmp("<=",id[danci]) ==0)
            {
                token[t] = 22;
            }
            if(strcmp(">",id[danci]) ==0)
            {
                token[t] = 23;
            }
            if(strcmp(">=",id[danci]) ==0)
            {
                token[t] = 24;
            }
            if(strcmp("=",id[danci]) ==0)
            {
                token[t] = 25;
            }
            if(strcmp(";",id[danci]) ==0)
            {
                token[t] = 26;
            }
            if(strcmp("(",id[danci]) ==0)
            {
                token[t] = 27;
            }
            if(strcmp(")",id[danci]) ==0)
            {
                token[t] = 28;
            }
            if(strcmp("#",id[danci]) ==0)
            {
                token[t] = 0;
            }
            t++;
        }

        if(shuzi(sentence[k]))
        {
            shuzichuan++;
            num[shuzichuan][dancilong] = sentence[k];
            k++;
            while(shuzi(sentence[k]) && k<i)
            {
                dancilong++;
                num[shuzichuan][dancilong] = sentence[k];
                k++;
            }
            dancilong = 0;
            token[t++] = 11;
        }
    }

    int n = 0;
     x = 0;//id计数
     int y = 0;//num计数
    while(n < t)
    {
        if(token[n] == 11)
        {
            cout<<"("<<token[n]<<",";
            showstring(num[y++]);
            cout<<")";
            //y++;
        }
        else
        {
            cout<<"("<<token[n]<<",";
            showstring(id[x++]);
            cout<<")";
        }
        n++;
    }


}

void main()
{
    fenxi();
}