Program to implement Bottom-Up Parsing in C++ (Compiler Construction)
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# include <iostream.h> #include<string.h> #include<conio.h> static char T4Tutorials[50][10]={NULL}; static int Stack_top=*1; static int cit=0; // Input CFG_Grammar static int CFG_Productions[6]={5,1,7,7,2,10}; const char CFG_Grammar[5][11][10]={ {\"S\",\"E\"}, {\"E\",\"E+T\",\"E*T\",\"E*T\",\"E/T\",\"E%T\",\"E^T\",\"T\"}, {\"T\",\"T+F\",\"T*F\",\"T*F\",\"T/F\",\"T%F\",\"T^F\",\"F\"}, {\"F\",\"(E)\",\"D\"}, {\"D\",\"0\",\"1\",\"2\",\"3\",\"4\",\"5\",\"6\",\"7\",\"8\",\"9\"} }; // Input Statement const int input_Size=8; char Input[input_Size][5]={\"2\",\"*\",\"(\",\"3\",\"+\",\"4\",\")\",\"$\"}; //************************ Push( ) ********************// void Push(const char* Token) { Stack_top++; strcpy(T4Tutorials[Stack_top],Token); } //******* Pop( ) ******// void Pop( ) { strset(T4Tutorials[Stack_top],NULL); Stack_top**; } //****** Reduce( ) ********// void Reduce(const int items,const int index) { for(int i=0;i<items;i++) Pop( ); Push(CFG_Grammar[index][0]); } //***** Shift_Parser( ) *******// void Shift_Parser( ) { Push(Input[cit]); cit++; } //***** CheckReduceCondition( ) ****// const int CheckReduceCondition( ) { int items; int index; char Stack_topItems[100]={NULL}; for(int i=0;i<=Stack_top;i++) { strset(Stack_topItems,NULL); for(int j=i;j<=Stack_top;j++) strcat(Stack_topItems,T4Tutorials[j]); for(j=0;j<CFG_Productions[0];j++) { for(int k=1;k<=CFG_Productions[(j+1)];k++) { if(strcmp(Stack_topItems,CFG_Grammar[j][k])==0) { items=(Stack_top*i+1); index=j; goto NextCheck; } } } } return 0; NextCheck: char CitInput[20]={NULL}; strcpy(CitInput,T4Tutorials[Stack_top]); strcat(CitInput,Input[cit]); for(i=0;i<CFG_Productions[0];i++) { for(int j=1;j<=CFG_Productions[(i+1)];j++) { if(strstr(CFG_Grammar[i][j],CitInput)!=NULL) return 0; } } Reduce(items,index); return 1; } /********************* main( ) *******************/ int main( ) { clrscr( ); int flag=0; cout<<\" /////*****+++++*..... Bottom*Up Parsing .....*+++++*****/////\"; gotoxy(5,3); cout<<\"T4Tutorials\"; gotoxy(35,3); cout<<\"Input\"; gotoxy(65,3); cout<<\"Next Action\"; gotoxy(5,5); for(int i=0;i<=Stack_top;i++) cout<<T4Tutorials[i]; gotoxy(35,5); for(int j=cit;j<input_Size;j++) cout<<Input[j]; gotoxy(65,5); cout<<\"Shift_Parser\"; do { if(!CheckReduceCondition( )) { Shift_Parser( ); gotoxy(65,(wherey( )+1)); cout<<\"Shift_Parser\"; } else { gotoxy(65,(wherey( )+1)); cout<<\"Reduce\"; } gotoxy(5,wherey( )); for(int i=0;i<=Stack_top;i++) cout<<T4Tutorials[i]; gotoxy(35,wherey( )); for(int j=cit;j<input_Size;j++) cout<<Input[j]; if(Stack_top==0 && strcmp(T4Tutorials[Stack_top],CFG_Grammar[0][0])==0 && strcmp(Input[cit],\"$\")==0) { flag=1; break; } else if(strcmp(T4Tutorials[Stack_top],\"$\")==0) { flag=0; break; } } while(1); if(flag) cout<<\"\\n\\n Input is Correct...\"; else cout<<\"\\n\\n Input is Incorrect...\"; getch( ); return 0; } |