Lex File
%{
#include < stdio.h >
#include < stdlib.h >
int op_c = 0, id_c = 0, bc = -1;
int id[10];
char op[10],br[10];
%}
%%
[0-9]+ { id[id_c++] = atoi(yytext); }
[+\-*/] { op[op_c++] = yytext[0]; }
"(" {br[++bc]='(';}
")" {if(br[bc]!='('){printf("Invalid\n");exit(0);}else{--bc;}}
[\n] {return 0;}
. { printf("Invalid character: %s\n", yytext); }
%%
int main() {
yylex();
if (id_c > op_c && bc == -1 || (op_c==0&&id_c==0)) {
printf("\nIdentifiers (%d): ", id_c);
for (int i = 0; i < id_c; i++)
printf("%d\t", id[i]);
printf("\nOperators (%d): ", op_c);
for (int i = 0; i < op_c; i++)
printf("%c\t", op[i]);
printf("\n");
} else {
printf("Invalid expression\n");
}
return 0;
}Yacc File
%{
#include< stdio.h >
#include< stdlib.h >
int result;
%}
%token NUM
%left '+' '-'
%left '*' '/'
%%
S: E {result=$1;}
E: E '+' E {$$=$1+$3;}
| E '-' E {$$=$1-$3;}
| E '*' E {$$=$1*$3;}
| E '/' E {if($3!=0)$$=$1/$3;else{printf("Invalid\n");exit(0);}}
| '(' E ')' {$$=$2;}
| NUM;
%%
int main(){
printf("Enter Expression:");
yyparse();
printf("Result: %d\n",result);
}yyerror(){
printf("Invalid\n");
exit(0);
}Lex File
%{
#include "y.tab.h"
%}
%%
[0-9]+ {yylval=atoi(yytext);return NUM;}
[ \t] ;
\n {return 0;}
. {return yytext[0];}
%%Yacc File
%{
#include< stdio.h >
#include< stdlib.h >
%}
%token A B
%%
S: C
C: A C | B;
%%
int main(){
printf("Enter String:");
yyparse();
printf("Valid\n");
}yyerror(){
printf("Invalid\n");
exit(0);
}Lex File
%{
#include "y.tab.h"
%}
%%
[a] {return A;}
[b] {return B;}
[ \t] ;
\n {return 0;}
. {return yytext[0];}
%%C File
#include< stdio.h >
#include< stdlib.h >
#include< string.h >
char a[20],stk[20];
int i=0,j=0,c=0,length;
void check(){
int z;
for(z=0;z< length;z++){
if(stk[z]=='i'&&stk[z+1]=='d'){
printf("\n$%s\t\t%s$\t\tReduce id",stk,a);
stk[z]='E';
stk[z+1]=' ';
j++;
}
}
for(z=0;z< length;z++){
if(stk[z]=='E'&&(stk[z+1]=='+'||stk[z+1]=='*')&&stk[z+2]=='E'){
printf("\n$%s\t\t%s$\t\tReduce %c%c%c",stk,a,stk[z],stk[z+1],stk[z+2]);
stk[z]='E';
stk[z+1]=' ';
stk[z+2]=' ';
i-=2;
}
}
for(z=0;z< length;z++){
if(stk[z]=='('&&stk[z+1]=='E'&&stk[z+2]==')'){
printf("\n$%s\t\t%s$\t\tReduce %c%c%c",stk,a,stk[z],stk[z+1],stk[z+2]);
stk[z]='E';
stk[z+1]=' ';
stk[z+2]=' ';
i-=2;
}
}
}
void main(){
printf("Given Grammar:\nE- > E+E\n |E*E\n |(E)\n |id\n");
printf("Enter input:");
scanf("%s",a);
length=strlen(a);
printf("Stack\t\tInput\t\tAction");
for(i=0,j=0;j< length;j++,i++){
if(a[j]=='i'&&a[j+1]=='d'){
printf("\n$%s\t\t%s$\t\tShift id",stk,a);
stk[i]=a[j];
stk[i+1]=a[j+1];
stk[i+2]='\0';
a[j]=' ';
a[j+1]=' ';
check();
}else{
printf("\n$%s\t\t%s$\t\tShift %c",stk,a,a[j]);
stk[i]=a[j];
stk[i+1]='\0';
a[j]=' ';
check();
}
}
printf("\n$%s\t\t%s$\n",stk,a);
}C File
#include < stdio.h >
#include < stdlib.h >
#include < string.h >
int main() {
char res[32], arg1[32], op[32], arg2[32];
FILE *inFile = fopen("in.txt", "r");
FILE *outFile = fopen("out.txt", "w");
while (1) {
fscanf(inFile, "%s %s %s %s", res, arg1, op, arg2);
if (!strcmp(res, "----")) break;
if (!strcmp(op, "=")) {
fprintf(outFile, "MOV R0, %s\n", arg1);
fprintf(outFile, "MOV %s, R0\n", res);
} else {
fprintf(outFile, "MOV R0, %s\n", arg1);
if (!strcmp(op, "+")) {
fprintf(outFile, "ADD R0, %s\n", arg2);
} else if (!strcmp(op, "-")) {
fprintf(outFile, "SUB R0, %s\n", arg2);
} else if (!strcmp(op, "*")) {
fprintf(outFile, "MUL R0, %s\n", arg2);
} else if (!strcmp(op, "/")) {
fprintf(outFile, "DIV R0, %s\n", arg2);
}
fprintf(outFile, "MOV %s, R0\n", res);
}
}
fclose(inFile);
fclose(outFile);
return 0;
}
in.txt File
T1 -B = ?
T2 C + D
T3 T1 * T2
A T3 = ?
----Lex File
%{
#include< stdio.h >
#include< string.h >
int count=0;
%}
%%
"//".* {count++;}
("/*"(.|\n)*"*/") {count++;}
. {fprintf(yyout,"%s",yytext);}
%%
int main(){
char inFile[20],outFile[20];
strcpy(inFile,"in.c");
strcpy(outFile,"out.c");
yyin=fopen(inFile,"r");
yyout=fopen(outFile,"w");
yylex();
printf("%d Comments removed from %s and written to %s\n",count,inFile,outFile);
}in.c File
#include
/*
* This program calculates the factorial of a number
* entered by the user.
* It uses a loop (iterative approach) to compute the factorial.
*/
int factorial(int n) {
int result = 1;
// Multiply result by all numbers from 1 to n
for (int i = 1; i < = n; i++) {
result *= i; // result = result * i
}
return result; // Return the final factorial value
}
int main() {
int number;
// Prompt user for input
printf("Enter a positive integer: ");
scanf("%d", &number);
// Validate input
if (number < 0) {
// Negative numbers do not have factorials
printf("Factorial is not defined for negative numbers.\n");
} else {
// Display the factorial result
printf("Factorial of %d is %d\n", number, factorial(number));
}
return 0; // Exit the program
}
Yacc File
%{
#include< stdio.h >
#include< stdlib.h >
int k=0,i=0,o=0,d=0;
extern FILE *yyin;
%}
%token KEY OP DIGIT ID
%%
S: KEY S {k++;}
| ID S {i++;}
| DIGIT S {d++;}
| OP S {o++;}
| OP {o++;}
| ID {i++;}
| KEY {k++;}
| DIGIT {d++;}
%%
int main(){
yyin=fopen("input.c","r");
do{
yyparse();
}while(!feof(yyin));
printf("K:%d\nI:%d\nD:%d\nO:%d\n",k,i,d,o);
}yyerror(){
printf("Invalid");
exit(0);
}Lex File
%{
#include "y.tab.h"
%}
%%
"if"|"int"|"else"|"return"|"printf"|"void"|"main"|"for"|"while" {printf("Keyword is %s\n",yytext);return KEY;}
[a-zA-Z_][a-zA-Z_0-9]* {printf("Identifier is %s\n",yytext);return ID;}
[0-9]+ {yylval=atoi(yytext);printf("Digit is %d\n",yylval),return DIGIT;}
[ > < \+\-\*\/\=\(\)] {printf("Operator is %s\n",yytext);return OP;}
.|\n ;
%%input.c File
#include < stdio.h >
void main() {
int i;
for(i = 0; i < 5; i++) {
if(i % 2 == 0) {
printf("Even\n");
} else {
printf("Odd\n");
}
}
return;
}