实验：词法分析

#include<stdio.h>
#include<stdalign.h>
#define M 100
main()
{
    int i,i1=0,i2=0,j;
    char n[M],n1[M],n2[M];
    printf("请输入一串数据：（数字，字母，界符，运行符）\n");
    gets(n);
      for(i=0;i<n;i++)
    {
        j=(int)n[i];
        n1[i]=n[M];
        if((j>=65)&&(j<=90)||(j>=90)&&(j<=122))
        {
            n1[i1]=n[i];
            i1++;
        }
        else{
             while(i1!=0)
            {
               n1[i1]='\0';
               if(  strcmp(n1,"auto")==0||strcmp(n1,"int")==0||strcmp(n1,"double")==0||strcmp(n1,"long")==0
                  ||strcmp(n1,"char")==0||strcmp(n1,"float")==0||strcmp(n1,"short")==0||strcmp(n1,"signed")==0
                  ||strcmp(n1,"unsigned")==0||strcmp(n1,"struct")==0||strcmp(n1,"union")==0||strcmp(n1,"enum")==0
                  ||strcmp(n1,"static")==0||strcmp(n1,"switch")==0||strcmp(n1,"case")==0||strcmp(n1,"default")==0
                  ||strcmp(n1,"break")==0||strcmp(n1,"register")==0||strcmp(n1,"const")==0||strcmp(n1,"volatile")==0
                  ||strcmp(n1,"typedef")==0||strcmp(n1,"extern")==0||strcmp(n1,"return")==0||strcmp(n1,"void")==0
                  ||strcmp(n1,"continue")==0||strcmp(n1,"do")==0||strcmp(n1,"while ")==0||strcmp(n1,"if")==0
                  ||strcmp(n1,"else")==0||strcmp(n1,"for")==0||strcmp(n1,"goto")==0||strcmp(n1,"sizeof")==0)
             {
               n1[i1]=')';
               printf("(1，");
               puts(n1);
               i1=0;
               memset(n1,0,100);
             }
              else
             {
               n1[i1]=')';
               printf("(10，");
               puts(n1);
               i1=0;
               memset(n1,0,100);
             }
           }

          if((j>48)&& (j<57))
         {
             n2[i2]=n[i];
             i2++;
         }
         else{
               if((int) n[i-1]>48 && (int) n[i-1]<57)
               {
               n2[i2]=')';
               printf("(11，");
               puts(n2);
               i2=0;
               memset(n2,0,100);
               }
         if(j==42||j==43||j==45||j==47||j==61||j==62||j==60)
        {

            if((int) n[i+1]==61)
            {
             switch (j)
             {
               case 60:
                      printf("(21，%c=)",n[i]);
                      printf("\n");
                      break ;
               case 62:
                      printf("(24，%c=)",n[i]);
                      printf("\n");
                      break;
              default :
                      printf("(非法字符，%c)",n[i]);
                      printf("\n");
                      break;
             }
             i=i+1;
            }
            else
            {
             switch (j)
             {
               case 42:
                      printf("(15，%c)",n[i]);
                      printf("\n");
                      break ;
               case 43:
                      printf("(13，%c)",n[i]);
                      printf("\n");
                      break;
               case 45:
                      printf("(14，%c)",n[i]);
                      printf("\n");
                      break;
               case 60:
                      printf("(20，%c)",n[i]);
                      printf("\n");
                      break;

               case 61:
                      printf("(25，%c)",n[i]);
                      printf("\n");
                      break;
               case 62:
                      printf("(24，%c)",n[i]);
                      printf("\n");
                      break;
               default :
                      printf("(非法字符，%c)",n[i]);
                      printf("\n");
                      break;
             }
            }
        }
        else if(j==32)
        {
             printf("\n");
        }
        else if(j==33||j==44||j==46||j==58||j==59||j==63||j==44)
        {
            switch (j)
             {
               case 59:
                      printf("(26，%c)",n[i]);
                      printf("\n");
                      break ;
               default :
                      printf("(非法字符，%c)",n[i]);
                      printf("\n");
                      break;
             }
        }
        else if(j==34||j==35||j==38||j==39||j==40||j==41||j==123||j==124||j==125||j==126)
        {
            switch (j)
             {
               case 40:
                      printf("(27，%c)",n[i]);
                      printf("\n");
                      break ;
               case 41:
                      printf("(28，%c)",n[i]);
                      printf("\n");
                      break ;
               case 35:
                      printf("(0，%c)",n[i]);
                      printf("\n");
                      break ;
               default :
                      printf("(非法字符，%c)",n[i]);
                      printf("\n");
                      break;
             }
        }
        else
        {
            break;
        }
     }
    }
  }
}

 

来源：https://www.cnblogs.com/wenjian1027/p/5979852.html