C PROGRAM - OPERATOR PRECEDENCE PARSER

/*OPERATOR PRECEDENCE PARSER*/ #include<stdio.h> #include<conio.h> void main() { char stack[20],ip[20],opt[10][10][1],ter[10]; int i,j,k,n,top=0,col,row; clrscr(); for(i=0;i<10;i++){stack[i]=NULL; ip[i]=NULL; for(j=0;j<10;j++){opt[i][j][1]=NULL;}} printf("Enter the no.of terminals:"); scanf("%d",&n); printf("\nEnter the terminals:"); scanf("%s",ter); printf("\nEnter the table values:\n"); for(i=0;i<n;i++) { for(j=0;j<n;j++) { printf("Enter the value for %c %c:",ter[i],ter[j]); scanf("%s",opt[i][j]); } } printf("\nOPERATOR PRECEDENCE TABLE:\n"); for(i=0;i<n;i++){printf("\t%c",ter[i]);} printf("\n"); for(i=0;i<n;i++){printf("\n%c",ter[i]); for(j=0;j<n;j++){printf("\t%c",opt[i][j][0]);}} stack[top]='$'; printf("\nEnter the input string:"); scanf("%s",ip); i=0; printf("\nSTACK\t\t\tINPUT STRING\t\t\tACTION\n"); printf("\n%s\t\t\t%s\t\t\t",stack,ip); while(i<=strlen(ip)) { for(k=0;k<n;k++) { if(stack[top]==ter[k]) col=k; if(ip[i]==ter[k]) row=k; } if((stack[top]=='$')&&(ip[i]=='$')){ printf("String is accepted"); break;} else if((opt[col][row][0]=='<') ||(opt[col][row][0]=='=')) { stack[++top]=opt[col][row][0]; stack[++top]=ip[i];  printf("Shift %c",ip[i]);  i++;   } else{  if(opt[col][row][0]=='>') { while(stack[top]!='<'){--top;} top=top-1; printf("Reduce"); } else { printf("\nString is not accepted"); break; } } printf("\n"); for(k=0;k<=top;k++) { printf("%c",stack[k]); } printf("\t\t\t"); for(k=i;k<strlen(ip);k++){ printf("%c",ip[k]); } printf("\t\t\t"); } getch(); }