编译原理实验
#include<iostream.h>
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int i,j,k,flag,number,status;
/*status which is use to judge the string is keywords or not!*/
char ch;
char words[10] = {" "};
char program[500];
int Scan(char program[])
{
char *keywords[13] = {"void","main","if","then","break","int", "char", "float", "include","for","while","printf", "scanf"};
number = 0; status = 0;
j = 0;ch = program[i++]; /* To handle the lettle space ands tab*/
/*handle letters*/
if ((ch >= 'a') && (ch <= 'z' ))
{
while ((ch >= 'a') && (ch <= 'z' ))
{
words[j++]=ch;
ch=program[i++];
}
i--;
words[j++] = '\0';
for (k = 0; k < 13; k++)
if (strcmp (words,keywords[k]) == 0)
switch(k) {
case 0:{
flag = 1; status = 1; break;
}
case 1:{
flag = 2; status = 1; break;
}
case 2:{
flag = 3; status = 1; break;
}
case 3:{
flag = 4; status = 1; break;
}
case 4:{
flag = 5;
status = 1;
break;
}
case 5:{
flag = 6;
status = 1;
break;
}
case 6:{
flag = 7;
status = 1;
break;
}
case 7:{
flag = 8;
status = 1;
break;
}
case 8:{
flag = 9;
status = 1;
break;
}
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