CDSS

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//1
//1a:Program to count the number, words, spaces and lines in a given input file

%{
#include<stdio.h>
int c=0;
int w=0;
int s=0;
int l=0;
%}
%%
" "{ s++; w++;}
[\n]{l++;w++;}
[\t\n]{w++;}
[^\t\n]{c++;}
%%
void yywrap()
{
return 1;
}
void main()
{
 yyin=fopen("Info.txt", "r");
 yylex();
 printf("Characters = %d\nWords = %d\nSpaces = %d\nLines= %d\n",c,w,s,l);
 return 0;
}

//op
lex 1a.l
cc lex.yy.c -ll
./a.out

//1b:Program to recognize and count the number of identifiers in a file

%{
#include<stdio.h>
int i=0;
%}
digit [0-9]
letter [a-z A-Z_]
%%
{letter}({letter}|{digit})*{i++;}
{digit}({letter}|{digit})*{i;}
%%
void main()
{
printf("Enter the values:\n");

yylex();
printf("Number of identifiers = %d\n", i);
return 0;
}

//op
lex 1b.l
cc lex.yy.c -ll
./a.out

// ctrl+d to end loop
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//2
//2a:Programs to count the numbers of comments lines in a given C program. Also eliminate them and copy the resulting program into separate file.

%{
#include<stdio.h>
int ml=0;
int sl=0;
%}

%%

"/*"[a-z A-Z 0-9 ' '\t \n]*"*/"ml++;
"//".*sl++;

%%
void main()
{
yyin=fopen("f1.txt","r");
yyout=fopen("f2.txt","w");
yylex();
fclose(yyin);
fclose(yyout);
printf("Number of single line comments =%d\n",sl);
printf("Number of multi line comments =%d\n",ml);
}

//op
gedit f1.txt
lex 2a.l
cc lex.yy.c -ll
cat f2.txt


//2b: Program to recognize whether a given sentence is simple or compound.

%{
#include<stdio.h>
int c=0;
%}

%%
[a-zA-Z]*[ ](and|or|but|yet|so)[ ][a-zA-Z]*{c=1;}
.|[\n];

%%
int yywrap()
{
  return 1;
}

int main()
{
 printf("enter the text\n");
 yylex();
 if(c)
 {
  printf("The given statement is compound\n");
 }
 else
 {
  printf("The given statement is simple\n");
 }
}


//op
lex 2b.l
cc lex.yy.c -ll
./a.out

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//3
//3a: Program to count number of:
 //    i.+ve and -ve integers
 //    ii. +ve and -ve fractions

%{
#include<stdio.h>
int pi=0,ni=0,pf=0,nf=0;
%}
%%
[-][0-9]+{ni++;}
[+]?[0-9]+{pi++;}
[-][0-9]*\.[0-9]+{nf++;}
[+]?[0-9]*\.[0-9]+{pf++;}
%%

void main(int argc,char *argv[])
{
if(argv!=2)
{
printf("usage :./a.out in.txt \n");
exit(0);
}
yyin=fopen(argc[1],"r");
yylex();
printf("Number of positive integer %d\n",pi);
printf("Number of negative integer %d\n",ni);
printf("Number of positive fraction %d\n",pf);
printf("Number of negative fraction %d\n",nf);
}
int yywrap(){
return 1;
}

//in.txt
12
-29
0
+8
-0.9

//op
lex 3a.l
cc lex.yy.c -ll
./a.out in.txt


//3b: Program to count the number of “scanf” and “printf” statements in a C program. Replace them with “readf” and “writef” statements respectively.

%{
#include<stdio.h>
int sf=0,pf=0;
%}
%%
"scanf"{sf++; fprintf(yyout,"readf");}
"printf"{pf++; fprintf(yyout,"writef");}
%%

void main()
{
yyin=fopen("f1.c","r");
yyout=fopen("f2.c","w");
yylex();
printf("no of scanf =%d\n no of printf =%d\n",sf,pf);
return 0;
}

//op
gedit f1.c
lex 3b.l
cc lex.yy.c -ll
./a.out
cat f2.c

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//4: Program to evaluate arithmetic expression involving operators +, -, *, /
//4.l
%{
#include "y.tab.h"
extern yylval;
%}
%%
[0-9]+{yylval=atoi(yytext);return num;}
[\+\-\*\/]{return yytext[0];}
[)]{return yytext[0];}
[(]{return yytext[0];}
.{;}
\n{return 0;}
%%

//4.y
%{
#include<stdio.h>
#include<stdlib.h>
%}
%name parse
%token num
%left'+''-'
%left'*''/'
%%
input:exp {printf("%d\n",$$);exit(0);}
exp:exp'+'exp   {$$=$1+$3;}
|exp'-'exp      {$$=$1-$3;}
|exp'*'exp      {$$=$1*$3;}
|exp'/'exp{     if($3==0){printf("Divide by zero error\n ");
exit(0);}
else
$$=$1/$3;}
|'('exp')'{$$=$2;}
|num{$$=$1;};
%%
int yyerror()
{
printf("error");
exit(0);
}
int main()
{
printf("Enter an expression:\n");
yyparse();
}


//op
lex 4.l
yacc -d 4.y
cc lex.yy.c y.tab.c -lfl
./a.out

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//5: Program to recognize a valid variable which starts with a letter, followed by any number of letter or digits
//p5.l
%{
#include "y.tab.h"
%}
%%
[a-zA-z] return L;
[0-9] return D;

%%

//p5.y
%{
#include<stdio.h>
#include<stdlib.h>
%}
%name parse
%token L D

%%
var:L E {printf("Valid Variable\n"); return 0;}
E:E L;
|E D;
%%

int main()
{
printf("Type the variable\n");
yyparse();
return 0;
}
int yyerror()
{
printf("Invalid Variable\n");
exit(0);
}

//op
lex p5.l
yacc -d p5.y
cc lex.yy.c y.tab.c -lfl
./a.out

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//6: Program to recognize the strings using the grammar (a^nb^n ; n>=0)
//p6.l
%{
#include "y.tab.h"
%}
%%
a return A;
b return B;
. return yytext[0];
\n return yytext[0];
%%

//p6.y
%{
#include<stdio.h>
#include<stdlib.h>
%}
%name parse
%token A B

%%
Str:S '\n'{return 0;}
S:A S B;

| ;
%%

int main()
{
printf("Type the string\n");
if (!yyparse())
printf("Valid String\n");
return 0;
}
int yyerror()
{
printf("Invalid String\n");
exit(0);
}

//op
lex p6.l
yacc -d p6.y
cc lex.yy.c y.tab.c -lfl
./a.out
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//7: C program to implement Pass1 of Assembler

#include <stdio.h>
#include <string.h>
void main() {
  char opcode[10], operand[10], label[10], code[10], mnemonic[3];
  int locctr, start, length;

  FILE *fp1, *fp2, *fp3, *fp4;

  fp1 = fopen("ip.txt", "r");
  fp2 = fopen("optab.txt", "r");
  fp3 = fopen("symtabl.txt", "w");
  fp4 = fopen("out.txt", "w");

  fscanf(fp1, "%s\t%s\t%s", label, opcode, operand);

  if (strcmp(opcode, "START") == 0) {
    start = atoi(operand);
    locctr = start;
    fprintf(fp4, "\t%s\t%s\t%s\n", label, opcode, operand);
    fscanf(fp1, "%s\t%s\t%s", label, opcode, operand);
  } else
    locctr = 0;

  while (strcmp(opcode, "END") != 0) {
    fprintf(fp4, "%d\t", locctr);

    if (strcmp(label, "**") != 0) fprintf(fp3, "%s\t%d\n", label, locctr);
    fscanf(fp2, "%s\t%s", code, mnemonic);

    while (strcmp(code, "END") != 0) {
      if (strcmp(opcode, code) == 0) {
        locctr += 3;
        break;
      }
      fscanf(fp2, "%s\t%s", code, mnemonic);
    }
    if (strcmp(opcode, "WORD") == 0)
      locctr += 3;
    else if (strcmp(opcode, "RESB") == 0)
      locctr += atoi(operand);
    else if (strcmp(opcode, "BYTE") == 0)
      ++locctr;
    fprintf(fp4, "%s\t%s\t%s\t\n", label, opcode, operand);
    fscanf(fp1, "%s\t%s\t%s", label, opcode, operand);
  }
  fprintf(fp4, "%d\t%s\t%s\t%s\n", locctr, label, opcode, operand);
  length = locctr - start;
  printf("The length of the code:%d\n", length);

  fclose(fp1);
  fclose(fp2);

  fclose(fp3);
  fclose(fp4);
}

//1.Input.txt
**  START   2000
**  LDA FIVE
**  STA ALPHA
**  LDCH    CHARZ
**  STCH    C1
ALPHA   RESW    2
FIVE    WORD    5
CHARZ   BYTE    C'Z'
C1  RESB    1
**  END **


//op
gcc p7.c
./a.out
cat Symtabl.txt
cat Out.txt
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//8: C program to implement Absolute loader.

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
void main() {
    FILE fp;
    int i,l, j, staddrl;
    char name[10], line[50], namel[10], staddr[10];
    printf("enter program name: ");
    scanf("%s", name);
    fp = fopen("abssrc.txt", "r");
    fscanf(fp, "%s", line);
    for(i=2, j=0; i<8, j<6; i++, j++) {
        namel[j] = line[i];
    }
    namel[i] = '\0';
    printf("name from obj: %s\n", namel);
    if(strcmp(name,namel) == 0) {
        do {
            fscanf(fp, "%s", line);
            if(line[0] == 'T') {
                for(i=2, j=0; i<8, j<6; i++, j++) {
                    staddr[j] = line[i];
                }
                staddr[j] = '\0';
                staddrl = atoi(staddr);
                i=12;
                while(line[i] != '$') {
                    if(line[i] != '^') {
                        printf("00%d\t%c%c\n", staddrl, line[i], line[i+1]);
                        staddrl++;
                        i = i+2;
                    } else {
                        i++;
                    }
                }
            } else if (line[0] == 'E') {
                break;

            }
        }while(!feof(fp));
        fclose(fp);
    }
}


 //abssrc.txt
H^00COPY^001000
T^001000^3C^001011^10121A^11222B$
T^002000^2E^101B2A^0C123A$
E^001000
(or)
H^SAMPLE^001000^0035
T^001000^0C^001003^071009$
T^002000^03^111111$
E^001000

//op
./a.out
00COPY (or) SAMPLE

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