📄 ll17c.htm
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<p>下面是你输入的文法G：<br>
非终结符号集合为：{ S, Z, W, Y, V, U, E, A, T, B, F, X, C, M }<br>
终结符符号集合为：{ +, -, *, /, %, =, a, n, i, e, w, d, f, ;, (, ), {, }, r }<br>
a:id<br>
n:number<br>
i:if<br>
e:else<br>
w:while<br>
d:do<br>
f:for<br>
r:关系运算符<br>
<br>
G[S]:<br>
E->TA<br>
A->+TA<br>
A->@<br>
T->FB<br>
B->*FB<br>
B->@<br>
F->(E)<br>
F->a<br>
F->n<br>
S->W<br>
M->ErE<br>
M->@<br>
Z->a=E<br>
C->@<br>
W->i(M)XC<br>
X->{S}<br>
C->eX<br>
X->@<br>
S->Z;<br>
Y->w(M)X<br>
S->Y<br>
S->V;<br>
V->dXw<br>
S->U<br>
U->f(Z;M;Z)X<br>
A->-TA<br>
B->/FB<br>
B->%FB<br>
<br>可以推出空串的非终结符集合为：{ A, B, X, C, M }<BR>
<br>非终结符号的FIRST集合：<br>
FIRST(S) = { a, w, i, d, f }<br>
FIRST(Z) = { a }<br>
FIRST(W) = { i }<br>
FIRST(Y) = { w }<br>
FIRST(V) = { d }<br>
FIRST(U) = { f }<br>
FIRST(E) = { (, a, n }<br>
FIRST(A) = { +, @, - }<br>
FIRST(T) = { (, a, n }<br>
FIRST(B) = { *, @, /, % }<br>
FIRST(F) = { (, a, n }<br>
FIRST(X) = { {, @ }<br>
FIRST(C) = { @, e }<br>
FIRST(M) = { @, (, a, n }<br>
<br>非终结符号的FOLLOW集合：<br>
FOLLOW(S) = { #, } }<br>
FOLLOW(Z) = { ;, ) }<br>
FOLLOW(W) = { #, } }<br>
FOLLOW(Y) = { #, } }<br>
FOLLOW(V) = { ; }<br>
FOLLOW(U) = { #, } }<br>
FOLLOW(E) = { ), r, ; }<br>
FOLLOW(A) = { ), r, ; }<br>
FOLLOW(T) = { +, -, ), r, ; }<br>
FOLLOW(B) = { +, -, ), r, ; }<br>
FOLLOW(F) = { *, /, %, +, -, ), r, ; }<br>
FOLLOW(X) = { e, #, w, } }<br>
FOLLOW(C) = { #, } }<br>
FOLLOW(M) = { ), ; }<br>
<br>各产生式的SELECT集合：<br>
SELECT(E->TA) = { (, a, n }<br>
SELECT(A->+TA) = { + }<br>
SELECT(A->@) = { @, ), r, ; }<br>
SELECT(T->FB) = { (, a, n }<br>
SELECT(B->*FB) = { * }<br>
SELECT(B->@) = { @, +, -, ), r, ; }<br>
SELECT(F->(E)) = { ( }<br>
SELECT(F->a) = { a }<br>
SELECT(F->n) = { n }<br>
SELECT(S->W) = { i }<br>
SELECT(M->ErE) = { (, a, n }<br>
SELECT(M->@) = { @, ), ; }<br>
SELECT(Z->a=E) = { a }<br>
SELECT(C->@) = { @, #, } }<br>
SELECT(W->i(M)XC) = { i }<br>
SELECT(X->{S}) = { { }<br>
SELECT(C->eX) = { e }<br>
SELECT(X->@) = { @, e, #, w, } }<br>
SELECT(S->Z;) = { a }<br>
SELECT(Y->w(M)X) = { w }<br>
SELECT(S->Y) = { w }<br>
SELECT(S->V;) = { d }<br>
SELECT(V->dXw) = { d }<br>
SELECT(S->U) = { f }<br>
SELECT(U->f(Z;M;Z)X) = { f }<br>
SELECT(A->-TA) = { - }<br>
SELECT(B->/FB) = { / }<br>
SELECT(B->%FB) = { % }<br>
<br><b>输入的文法是一个LL(1)文法。</b><br>下面是生成的预测分析表：<BR>
<table border="1" cellpadding="0" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111">
<tr>
<td nowrap width="25"> </td>
<td nowrap width="25"> +</td>
<td nowrap width="25"> -</td>
<td nowrap width="25"> *</td>
<td nowrap width="25"> /</td>
<td nowrap width="25"> %</td>
<td nowrap width="25"> =</td>
<td nowrap width="25"> a</td>
<td nowrap width="25"> n</td>
<td nowrap width="25"> i</td>
<td nowrap width="25"> e</td>
<td nowrap width="25"> w</td>
<td nowrap width="25"> d</td>
<td nowrap width="25"> f</td>
<td nowrap width="25"> ;</td>
<td nowrap width="25"> (</td>
<td nowrap width="25"> )</td>
<td nowrap width="25"> {</td>
<td nowrap width="25"> }</td>
<td nowrap width="25"> r</td>
<td nowrap width="120"> #</td>
</tr>
<tr>
<td nowrap width="25"> S</td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> Z;</td>
<td nowrap width="120"> </td>
<td nowrap width="120"> W</td>
<td nowrap width="120"> </td>
<td nowrap width="120"> Y</td>
<td nowrap width="120"> V;</td>
<td nowrap width="120"> U</td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
</tr>
<tr>
<td nowrap width="25"> Z</td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> a=E</td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
</tr>
<tr>
<td nowrap width="25"> W</td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> i(M)XC</td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
</tr>
<tr>
<td nowrap width="25"> Y</td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> w(M)X</td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
</tr>
<tr>
<td nowrap width="25"> V</td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
<td nowrap width="120"> </td>
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