c语言实现算符优先语法分析

{
int t;
switch(ch)
{
case '+':t=0;break;
case '-':t=1;break;
case '*':t=2;break;
case '/':t=3;break;
case '(':t=4;break;
case ')':t=5;break;
case 'i':t=6;break;
case'-':zhongjian[q++]='-';break;
case'*':zhongjian[q++]='*';break;
case'/':zhongjian[q++]='/';break;
case'(':zhongjian[q++]='(';break;
case')':zhongjian[q++]=')';break;
break;
}
}
while(syn!=0);
}
void main()
{
loadch();
saomiao();
if(syn==0)
{
chu();
analyse();
printf("#E\t#\t结束\n");
if (syn==0)
{
printf("该字符串可被文法识别\n");
printf("E");
case'i':zhongjian[q++]='i';break;
case'#':zhongjian[q++]='#';syn=0;break;
default: syn=-1;break;
}
}
void saomiao()
{
p=0;q=0;
do
{
scaner();
if(syn==-1)
{
printf("输入符号有误!\n");
d=putzhong();
a=findint(zh);
b=findint(ch);
if (table[a][b]==-1)
{
push(ch);
j++;
printf("移进\n");
}
else if (table[a][b]==1)
{
for(int m=d;m>=j;m--)
{
shu[c++]=zhongjian[m];
for(int i=c;i>=0;i--)
{
printf("%c",shu[i]);
}
printf("\n");
}
else
{
printf("该字符串不可被文法识别\n");
}
}
}
{
printf("%c",zhan[i]);
}
printf("\t");
}
int putzhong()//打印;
do
{
printf("%c",zhongjian[i]);
}while(zhongjian[i++] != '#');
printf("\t");
i-=2;
return i;
shu[c++]=' ';
shu[c++]='>';
shu[c++]='-';
shu[c++]=' ';
}
else
{
syn=-1;
break;
}
zh=ding();
ch=zhongjian[j];
}
}
void loadch()//读入所有字符串
{
int i=0;
printf("请输入要进行算符优先分析的字符串:\n");
char zhan[100];//数组栈
int z,j;//z为栈顶指针,j为zhongjian数组指针
void push(char ch)//入栈
{
zhan[z++]=ch;
}
void pop()//出栈
{
z--;
}
void putzhan()//打印栈内字符
{
for(int i=0;i<z;i++)
#include<stdio.h>
char prog[100],zhongjian[100],shu[500];
char ch,zh;
int syn,p,q,a,b,c,d; //p指向prog，q指向zhongjian
int table[8][8]={
{1,1,-1,-1,-1,1,-1,1},
{1,1,-1,-1,-1,1,-1,1},
do
{
ch=getchar();
prog[i++]=ch;
}
while(ch!='#');
}
void scaner()
{
syn=1;
ch=prog[p++];
while(ch==' '||ch=='\n')
{
ch=prog[p++];
}
switch(ch)
{
case'+':zhongjian[q++]='+';break;
{1,1,1,1,-1,1,-1,1},
{1,1,1,1,-1,1,-1,1},
{-1,-1,-1,-1,-1,-1,-1,0},
{1,1,1,1,0,1,0,1},
{1,1,1,1,0,1,0,1},
{-1,-1,-1,-1,-1,0,-1,-1}};
//存储算符优先关系表，大于为1，小于或等于为-1，其它为0表示出错
}
char ding()//获取栈顶元素，无视E
{
char a;
q=z-1;
do
{
a=zhan[q--];
}while(a=='E');
return a;
}
char ding2()//获取栈顶元素
{
char a;
q=z-1;
a=zhan[q];
return a;
}
int findint(char ch) /*将字符转为数字，以得到算符优先值*/
case '#':t=7;
}
return t;
}
void chu()//初始化
{
zhan[0]='#';
z=1;
c=0;
j=0;
syn=0;
zh=ding();
ch=zhongjian[j];
}
void analyse()//分析
{
while (zh!='#'||ch!='#')
{
putzhan();
}
for(int i=z-1;i>0;i--)
{
shu[c++]=zhan[i];
}
zh=ding2();
if(zh=='i') //当前比较为i,出栈一次
pop();
else //当前比较不为i,出栈三次
{
pop();
pop();
pop();
}
push('E'); //归约到E
printf("归约\n");