.
pt->nVt = nCh; pt->next = NULL;
if(NULL == first[U - 100]) {
first[U - 100] = pt; } else {
qt->next = pt; /*qt指向first集的最后一个元素*/ }
pt = pt->next; } } else {
pt = first[nCh - 100]; while(NULL != pt) {
ch = pt->nVt; if(-1 != ch) {
AddFirst(U, ch); }
pt = pt->next; } } }
bool HaveEmpty(int nVn) {
if(nVn < 100) return false;
struct collectNode *pt; pt = first[nVn - 100]; while(NULL != pt) {
if(-1 == pt->nVt) return true;
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pt = pt->next; }
return false; }
void Follow(int V) { int i;
struct pRNode *pt ;
if(100 == V) /*当为初始符时*/ AddFollow(V, -1, 0 ); for(i = 0; i < PNum; i++) {
pt = P[i].rHead;
while(NULL != pt && pt->rCursor != V) pt = pt->next; if(NULL != pt) {
pt = pt->next; if(NULL == pt) {
if(NULL == follow[P[i].lCursor - 100] && P[i].lCursor != V) {
Follow(P[i].lCursor); }
AddFollow(V, P[i].lCursor, 0); } else {
while(NULL != pt && HaveEmpty(pt->rCursor)) {
AddFollow(V, pt->rCursor, 1); pt = pt->next; }
if(NULL == pt) {
if(NULL == follow[P[i].lCursor - 100] && P[i].lCursor != V) {
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Follow(P[i].lCursor); }
AddFollow(V, P[i].lCursor, 0); } else {
AddFollow(V, pt->rCursor, 1); } } } } }
void AddFollow(int V, int nCh, int kind) {
struct collectNode *pt, *qt; int ch; pt = NULL; qt = NULL;
if(nCh < 100) /*为终结符时*/ {
pt = follow[V - 100]; while(NULL != pt) {
if(pt->nVt == nCh) break; else {
qt = pt; pt = pt->next; } }
if(NULL == pt) {
pt = (struct collectNode *)malloc(sizeof(struct collectNode)); pt->nVt = nCh; pt->next = NULL;
if(NULL == follow[V - 100])
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{
follow[V - 100] = pt; } else {
qt->next = pt; /*qt指向follow集的最后一个元素*/ }
pt = pt->next; } } else {
if(0 == kind) {
pt = follow[nCh - 100]; while(NULL != pt) {
ch = pt->nVt;
AddFollow(V, ch, 0); pt = pt->next; } } else {
pt = first[nCh - 100]; while(NULL != pt) {
ch = pt->nVt; if(-1 != ch) {
AddFollow(V, ch, 1); }
pt = pt->next; } } } }
/*输出first或follow集*/
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void ShowCollect(struct collectNode **collect) { int i;
struct collectNode *pt; i = 0;
while(NULL != collect[i]) {
pt = collect[i];
printf(\ while(NULL != pt) {
if(-1 != pt->nVt) {
printf(\ } else
printf(\ pt = pt->next; } i++; }
printf(\}
/*计算first和follow*/ void FirstFollow() { int i; i = 0;
while('\\0' != Vn[i]) {
if(NULL == first[i]) First(100 + i); i++; } i = 0;
while('\\0' != Vn[i]) {
if(NULL == follow[i])
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预测分析算法的设计与实现
