SYSTEM PROGRAMMING LAB

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Q 1: WAP to convert INFIX to POSTFIX notation.
[SOURCE CODE]
#include<stdio.h>
#include<conio.h>
#include<string.h>
#define MAX 20
char stack[MAX];
int top=-1;
char pop();
void push(char item);
int prcd(char symbol) // Precedence
{
switch(symbol)
{
case '+':
case '-':
return 2;
case '*':
case '/':
return 4;
case '^':
return 6;
case '(':
case ')':
case '#':
return 1;
default:
return 0;
}
}
int isoperator(char symbol)
{
switch(symbol)
{
case '+': case '-': case '*': case '/': case '^':
case '(': case ')': return 1;
default: return 0;
}
}
; 2
void convertip(char infix[],char postfix[])
{
int i,symbol,j=0;
stack[++top]='#';
for(i=0;i<strlen(infix);i++)
{
symbol=infix[i];
if(isoperator(symbol)==0)
{
postfix[j]=symbol;
j++;
}
else
{
if(symbol=='(')
push(symbol);
else if(symbol==')')
{
while(stack[top]!='(')
{
postfix[j]=pop();
j++;
}
pop();
} else{
if(prcd(symbol)>prcd(stack[top]))
push(symbol);
else{
while(prcd(symbol)<=prcd(stack[top]))
{
postfix[j]=pop();
j++;
}
push(symbol);
}//end of else.
}//end of else.
}//end of else.
}//end of for.
while(stack[top]!='#')
{
postfix[j]=pop();
j++;
}
postfix[j]='\0';//null terminate string.
}
; 3
void main()
{
char infix[20],postfix[20];
clrscr();
printf("Enter the valid infix string:\n");
gets(infix);
convertip(infix,postfix);
printf("The corresponding postfix string is:\n");
puts(postfix);
getch();
}
void push(char item)
{
top++;
stack[top]=item;
}
char pop()
{
char a;
a=stack[top];
top--;
return a;
}
; 4
Q 1: WAP to convert INFIX to POSTFIX notation.
[SCREENSHOTS]
Enter the valid infix string: a+b/c The corresponding postfix string is: abc/+
Enter the valid infix string: a+b-(c^3)*(r/4) The corresponding postfix string is: ab+c3^r4/*-
; 5
Q 2: WAP to convert INFIX to PREFIX notation.
[SOURCE CODE]
#include<iostream.h>
#include<string.h>
#include<conio.h>
#include<ctype.h>
char stack[50];
int top=-1,x;
void push(char elem)
{
top++;
stack[top]=elem;
}
char pop()
{
x=stack[top];
top--;
return(x);
}
int order(char elem)
{
switch(elem)
{
case '#': return 0;
case '(': return 1;
case ')': return 1;
case '+':
case '-': return 2;
case '*':
case '/': return 3;
}
return 10; //default case
}
void main()
{
char infix[50],postfix[50],elem,ch;
int len,c=0,i=0;
cout<<"Enter the infix expresssion:";
cin>>infix;
push('#');
len=strlen(infix);
for(i=0;i<len;i++)
{
ch=infix[i];
if( ch == '(')
push(ch);
else if(isalpha(infix[i]))
{
postfix[c]=infix[i];
c++;
}
else if( ch == ')')
; 6
{
while(stack[top]!='(')
{
postfix[c]=pop();
c++;
}
elem=pop();
}
else
{
while( order(stack[top]) >= order(ch) )
{
postfix[c]=pop();
c++;
}
push(ch);
}
}
while( stack[top] != '#')
{
postfix[c]=pop();
c++;
}
postfix[c]='\0';
cout<<"The Infix Expression is"<<" "<<infix<<endl;
cout<<"The Postfix Expression is"<<" "<<postfix<<endl;
getch();
}
; 7
Q 2: WAP to convert INFIX to PREFIX notation.
[SCREENSHOTS]
Enter the infix expresssion:a+b-c/d The Infix Expression is a+b-c/d The Postfix Expression is ab+cd/-
Enter the infix expresssion:a*b/r*c/(a-b) The Infix Expression is a*b/r*c/(a-b) The Postfix Expression is ab*r/c*ab-/
; 8
Q 3: WAP to read and write a string to a file.
[SOURCE CODE]
//Using Turbo C
#include<fstream.h>
#include<conio.h>
#include<process.h> //for exit
#include<stdio.h> //for gets()
void main ()
{
clrscr();
int choice;
char data[100];
char cdata;
//using constructor
ofstream WriteFile("TheFile.txt",ios::out);
//using open() method
ifstream ReadFile;
ReadFile.open("TheFile.txt",ios::in);
while(1)
{
cout<<"\n\nEnter your choice"<<endl;
cout<<"Enter 1 to write to file"<<endl;
cout<<"Enter 2 to read string from file"<<endl;
cout<<"Enter 3 to read 5th character from file"<<endl;
cout<<"Enter 0 for exit"<<endl;
cout<<"\nEnter your choice: ";
cin>>choice;
cout<<endl;
switch(choice)
{
case 1:
cout << "Writing a string to the file" << endl;
cout << "Enter a string: ";
gets(data);
WriteFile.seekp(0, ios::beg);
WriteFile << data <<endl;
break;
case 2:
cout << "Reading a string from the file" << endl;
ReadFile.seekg(0, ios::beg);
ReadFile >> data;
cout << data << endl;
break;
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case 3:
cout << "Reading 5th character from the file" << endl;
ReadFile.seekg(0, ios::beg);
for(int i=0; i<5; i++)
ReadFile >> cdata;
cout << cdata << endl;
break;
case 0:
ReadFile.close();
WriteFile.close();
exit(0);
}
}
}
; 10
Q 3: WAP to read and write a string to a file.
[SCREENSHOTS] Enter your choice Enter 1 to write to file Enter 2 to read string from file Enter 3 to read 5th character from file Enter 0 for exit Enter your choice: 1 Writing a string to the file Enter a string: Hello... Enter your choice Enter 1 to write to file Enter 2 to read string from file Enter 3 to read 5th character from file Enter 0 for exit Enter your choice: 2 Reading a string from the file Hello... Enter your choice Enter 1 to write to file Enter 2 to read string from file Enter 3 to read 5th character from file Enter 0 for exit Enter your choice: 3 Reading 5th character from the file o
; 11
Q 4: WAP to perform lexical analysis of an expression.
[SOURCE CODE]
#include<iostream.h>
#include<string.h>
#include<ctype.h>
#include<conio.h>
void main()
{
char s[50];
char operands[50];
char cons[50];
char oper[50];
int l=0,i=0,c=0,co=0,cou=0,count=0;
cout<<"Enter a string";
cin>>s;
l=strlen(s);
for(i=0;i<l;i++)
{
if(isalpha(s[i]))
{
operands[c]=s[i];
c++;
}
else if(isdigit(s[i]))
{
cons[co]=s[i];
co++;
}
else
{
oper[cou]=s[i];
cou++;
}
}
operands[c]='\0';
cons[co]='\0';
oper[cou]='\0';
count=c+co+cou;
cout<<"No of Operands:"<<" "<<c<<" "<<"\n\t They are:"<<" "<<operands<<endl;
cout<<"No of Operators:"<<" "<<cou<<" "<<"\n\t They are: "<<" "<<oper<<endl;
cout<<"No of Contants:"<<" "<<co<<" "<<"\n\tThey are: "<<" "<<cons<<endl;
cout<<"No of Tokens:"<<" "<<count<<endl;
getch();
}
; 12
Q 4: WAP to perform lexical analysis of an expression.
[SCREENSHOTS] Enter a string a*0=0 No of Operands: 1 They are: a No of Operators: 2 They are: *= No of Contants: 2 They are: 00 No of Tokens: 5
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Q 5: WAP to accept a string of the form a(a+b)*abc.
[SOURCE CODE]
#include<iostream.h>
#include<string.h>
#include<ctype.h>
#include<conio.h>
void main()
{
clrscr();
char s[100];
int l,flag=0,i=0;
cout<<"Enter the string:"<<endl;
cin>>s;
l=strlen(s);
if(s[0]=='a' && s[l-1]=='c' && s[l-2]=='b' && s[l-3]=='a')
{
for(i=1;i<l-3;i++)
{
if(s[i]!='a' && s[i]!='b' && s[i]!='+')
{
flag=1;
cout<<"Format is not accepted"<<endl;
break;
}
}
if(flag==0)
cout<<"Format is accepted"<<endl;
else
cout<<"Format is not accepted"<<endl;
}
else
cout<<"Format is not accepted"<<endl;
getch();
}
; 14
Q 5: WAP to accept a string of the form a(a+b)*abc.
[SCREENSHOTS] Enter the string: aababbbbabaabaabaaaaaaaabc Format is accepted Enter the string: aabc Format is accepted Enter the string: bab Format is not accepted
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Q 6: WAP to create a symbol table on analyzing the provided string.
[SOURCE CODE]
#include<iostream.h>
#include<stdio.h>
#include<string.h>
#include<ctype.h>
void main()
{
char in[50],dig[50],id[50];
int i=0,j=0,k,l=0;
cout<<"Enter the Expression:\t";
gets(in);
cout<<"\nKeyword\tIdentifier\tConstants\tOperators\tSpecialCharacters\n";
while(in[i]!='\0')
{
if(isalpha(in[i]))
{
j=0;
while((isalpha(in[i]))||(isdigit(in[i])))
{
id[j]=in[i];
i++;
j++;
}
id[j]='\0';
if(strcmp(id,"char")==0||strcmp(id,"int")==0||strcmp(id,"float")==0||strcmp(id,"if")==0 || strcmp(id,"then")==0 || strcmp(id,"while")==0 || strcmp(id,"do")==0||strcmp(id,"for")==0
||strcmp(id,"switch")==0||strcmp(id,"case")==0)
{
cout<<"\n";
for(l=0;l<j;l++)
cout<<""<<id[l];
}
else
{
cout<<"\t";
for(l=0;l<j;l++)
cout<<id[l];
}
}
else if(isdigit(in[i]))
{
k=0;
while(isdigit(in[i]))
{
dig[k]=in[i];
i++;
k++;
; 16
}
cout<<"\n\t\t\t";
for(l=0;l<k;l++)
cout<<dig[l];
}
else if(in[i]=='+'||in[i]=='-'||in[i]=='*'||in[i]=='/'||in[i]=='<'||in[i]=='>'||in[i]=='=')
{
cout<<"\t\t\t\t\t "<<in[i];
i++;
}
else if(in[i]==';'||in[i]==':'||in[i]=='.'||in[i]=='('||in[i]==')'||in[i]=='{'||in[i]=='}')
{
cout<<"\t\t\t\t\t\t\t "<<in[i];
i++;
}
else
i++;
cout<<"\n";
}
}

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Q 6: WAP to create a symbol table on analyzing the provided string.
[SCREENSHOTS] Enter the Expression: a+b/(c%2)=5 Keyword Identifier Constants Operators SpecialCharacters a + b / ( c 2 ) = 5
; 18
Q 7: WAP to create a text editor.
[SOURCE CODE]
#include<stdlib.h>
#include<iostream.h>
#include<conio.h>
#include<fstream.h>
#include<string.h>
char data[100];
ofstream of;
ifstream iif;
int ch;
char fname[10];
void main()
{
clrscr();
while(ch!=5)
{
cout<<" -- ";
cout<<"\n\n MAIN MENU \n";
cout<<" 1.Write \n";
cout<<" 2.Read \n";
cout<<" 3.Copy \n";
cout<<" 4.Paste \n";
cout<<" 5.Exit \n";
cout<<" Your Choice:";
cin>>ch;
switch(ch)
{
case 1:
cout<<"\nFILENAME=";
cin>>fname;
cout<<"WRITING TO THE FILE:";
of.open(fname);
cout<<"\nEnter DATA:"<<"\n";
cin>>data;
of<<data;
of.close();
break;
case 2:
cout<<"\nFILENAME=";
cin>>fname;
cout<<"\nREADING FROM THE FILE:";
iif.open(fname);
while(!iif.eof())
{
iif>>data;
cout<<endl;
cout<<data;
; 19
}
iif.close();
break;
case 3:
cout<<"\nFILENAME=";
cin>>fname;
cout<<"\nCOPYING FROM THE FILE:";
iif.open(fname);
while(!iif.eof())
{
iif>>data;
}
iif.close();
cout<<"\nDATA COPIED";
break;
case 4:
cout<<"\nFILENAME=";
cin>>fname;
cout<<"PASTING TO THE FILE:";
of.open(fname);
of<<data;
of.close();
cout<<"\nDATA PASTESD";
break;
default:
exit(0);
getch();
}
}
}
; 20
Q 7: WAP to create a text editor.
[SCREENSHOTS] MAIN MENU 1.Write 2.Read 3.Copy 4.Paste 5.Exit Your Choice:1 FILENAME=Mine.txt WRITING TO THE FILE: Enter DATA: Hello -- MAIN MENU 1.Write 2.Read 3.Copy 4.Paste 5.Exit Your Choice:2 FILENAME=Mine.txt READING FROM THE FILE: Hello -- MAIN MENU 1.Write 2.Read 3.Copy 4.Paste 5.Exit Your Choice:3 FILENAME=Mine.txt DATA COPIED -- MAIN MENU 1.Write 2.Read 3.Copy 4.Paste 5.Exit Your Choice:4 FILENAME=Mine2.txt PASTING TO THE FILE: DATA PASTED
; 21
Q 8: WAP to find the union and intersection of the two sets.
[SOURCE CODE]
#include<stdio.h>
#include<iostream.h>
#include<conio.h>
#include<process.h>

void Union(int set1[10],int set2[10],int m,int n);
void Intersection(int set1[10],int set2[10],int m,int n);

void main()
{

 clrscr();

 int a[10],b[10],m,n,i,j;
 int ch;

 cout<<"\nEnter the number of elements in first set:\n";
 cin>>m;

 cout<<"\nEnter the elements:\n";
 for(i=0;i<m;i++)
 cin>>a[i];

 cout<<"\nEnter the number of elements in second set:\n";
 cin>>n;

 cout<<"\nEnter the elements:\n";
 for(i=0;i<n;i++)
 cin>>b[i];

 while(1)
 {
  clrscr();


  cout<<"\n\nMenu:\n\n1. Find the Union\n2. Find the Intersection";
  cout<<"\n3. Exit";

  cout<<"\nEnter your choice:\n";
  cin>>ch;

  switch(ch) {
  case 1:
   Union(a,b,m,n);
   break;

  case 2:
   Intersection(a,b,m,n);
   break;

  case 3:
   exit(0);
  }
  getch();
 }
}
 
void Union(int a[10],int b[10],int m,int n)
{
 int c[20],i,j,k=0,flag=0;

 //add all elements of set A
 for(i=0;i<m;i++)
 {
  c[k]=a[i];
  k++;
 }

 //add all elements of set B (not in A)
 for(i=0;i<n;i++)
 {

  //check in A first
  flag=0;
  for(j=0;j<m;j++)
  {
   if(b[i]==c[j])
   {
    flag=1;
    break;
   }
  }

  if(flag==0)
  {
   c[k]=b[i];
   k++;
  }
 }

 cout<<"\nElement of resultant set\n\n";
 for(i=0;i<k;i++)
 {
  cout<<"\t"<<c[i];
 }
}

void Intersection(int a[10],int b[10],int m,int n)
{
 int c[20],i,j,k=0,flag=0;

 for(i=0;i<m;i++)
 {
  flag=0;
  for(j=0;j<n;j++)
  {
   if(a[i]==b[j])
   {
    flag=1;
    break;
   }
  }

  if(flag==1)
  {
   c[k]=a[i];
   k++;
  }
 }

 if(k==0)
 {
  cout<<"\n\nResultant set is null set!\n";
 }else{
  cout<<"\nElement of resultant set\n";
  for(i=0;i<k;i++)
  {
   cout<<"\t"<<c[i];
  }
 }
}


; 23
Q 8: WAP to find the union and intersection of the two sets.
[SCREENSHOTS] Enter the number of elements in first set: 5 Enter the elements: 1 2 3 4 5 Enter the number of elements in second set: 5 Enter the elements: 4 5 6 7 8 Menu: 1. Find the Union 2. Find the Intersection 3. Exit Enter your choice: 1 Element of resultant set 1 2 3 4 5 6 7 8 Menu: 1. Find the Union 2. Find the Intersection 3. Exit Enter your choice: 2 Element of resultant set 4 5