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#include<stdio.h>
#include<conio.h>
#include<string.h>
void main()
{
int i,l,k=7,p,j;
char a[50],b[89]="DLE STX",c[50];
clrscr();
printf("\n enter the data");
scanf("%s",a);
l=strlen(a);
for(i=0;i<l;i++)
{
if(a[i]=='D'&&a[i+1]=='L'&&a[i+2]=='E')
{
b[k]='D';
k++;
b[k]='L';
k++;
b[k]='E';
k++;
}
b[k]=a[i];
k++;
}
b[k]='\0';
strcat(b,"DLE ETX");
printf("%s",b);
p=strlen(b);
k=0;
for(i=7;i<(p-7);i++)
{
if(b[i]=='D'&&b[i+1]=='L'&&b[i+2]=='E')
{
for(j=i;j<i+3;j++)
{
c[k]=b[j];
k++;
}
i=i+6;
}
if(i<p-7)
{
c[k]=b[i];
k++;
}
}
c[k]='\0';
printf("\n %s",c);
getch();
}
OUTPUT:
Enter the data
: Ahcet
DLEETX Ahcet DLEETX
Ahcet
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#include<stdio.h>
#include<conio.h>
#include<string.h>
void main()
{
int i,l,k=8,p,j;
char a[50],b[70]="01111110",c[50];
clrscr();
printf("enter the data:");
scanf("%s",a);
l=strlen(a);
for(i=0;i<l;i++)
{
if(a[i]=='1'&&a[i+1]=='1'&&a[i+2]=='1'&&a[i+3]=='1'&&a[i+4]=='1')
{
for(j=i;j<i+5;j++)
{
b[k]=a[j];
k++;
}
i=i+5;
b[k]='\0';
k++;
}
b[k]=a[i];
k++;
}
b[k]='\0';
strcat(b,"01111110");
printf("%s",b);
p=strlen(b);
k=0;
for(i=8;i<(p-8);i++)
{
if(b[i]=='1'&&b[i+1]=='1'&&b[i+2]=='1'&&b[i+3]=='1'&&b[i+4]=='1')
{
for(j=i;j<i+5;j++)
{
c[k]=b[j];
k++;
}
i=i+6;
}
if(i<p-9)
{
c[k]=b[i];
k++;
}
}c[k]='\0';
printf("\n%s",c);
getch();
}
OUTPUT:
Enter the data11111
0111111011111001111110
the unstuff bit is11111
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.
|
Ceaser Cipher
#include<stdio.h>
#include<conio.h>
#include<string.h>
void main()
{
int i,len;
char src[20],dst[20];
clrscr();
printf("enter data:");
gets(src);
len=strlen(src);
strcpy(dst,src);
for(i=0;i<len;i++)
{
if(dst[i]==' ')
i++;
dst[i]=dst[i]-97;
dst[i]=(dst[i]+3)%26;
dst[i]=dst[i]+65;
}
dst[i]='\0';
printf("%s",dst);
getch();
}
OUTPUT:
Enter the string
: Uday
Enter encryption
code : 3
Encrypted data:
xgdb
Decrypted data:
Uday
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.
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DIJKSTRA ALGORITHM
#include<conio.h>
#include<stdio.h>
#define INFINITY
1000
#define permanent 1
#define tentative 0
struct state
{
int predecessor;
int length;
int label;
}state[100];
void
main()
{
int i,j,k,n,t,s,min,path[20],dist[100][100];
struct state *p;
clrscr();
printf("\n enter the no of
nodes:\t");
scanf("%d",&n);
printf("\n enter the dis bet nodes:\t");
for(i=0;i<n;i++)
for(j=i+1;j<n;j++)
{
printf("
%2d %2d ",i,j);
scanf("%d",&dist[i][j]);
dist[j][i]=dist[i][j];
}
for(i=0;i<n;i++)
dist[i][j]=0;
/******ADJACENCY
MATRIX*****/
printf("\n cost adjacency matrix is :");
printf("\n");
for(i=0;i<n;i++)
printf("%d ",i);
printf("\n-----------\n");
for(i=0;i<n;i++)
{
printf("%6d ",i);
for(j=0;j<n;j++)
{
printf("%6d
",dist[i][j]);
}
printf("\n");
}
printf("\n
enter src node:");
l1: scanf("%d",&s);
if(s<0||s>=n)
{
printf("pls enter valid src node:");
goto l1;
}
printf("\n enter des node:");
l2:scanf("%d",&t);
if(t<0||t>=n)
{
printf("pls enter valid des node:");
goto l2;
}
/*****shr path & min cost eval**/
for(p=&state[0];p<&state[n];p++)
{
p->predecessor=-1;
p->length=INFINITY;
p->label=tentative;
}
state[t].length=0;
state[t].label=permanent;
k=t;
do
{
for(i=0;i<n;i++)
if(dist[k][i]!=0&&state[i].label==tentative)
{
if(state[k].length+dist[k][i]<state[i].length)
{
state[i].predecessor=k;
state[i].length=state[k].length+dist[k][i];
}
}
k=0;
min=INFINITY;
for(i=0;i<n;i++)
if(state[i].label==tentative&&state[i].length<min)
{
min=state[i].length;
k=i;
}
state[k].label=permanent;
}
while(k!=s);
i=0;
k=s;
do
{
path[i++]=k;
k=state[k].predecessor;
}
while(k>=0);
printf("\n the shortest path is:");
printf("%d",path[0]);
for(j=1;j<i;j++)
printf("->%2d ",path[j]);
printf("\n cost of path is :%d",state[s].length);
getch();
}
OUTPUT:
Enter the number
of nodes: 4
Enter the dist.
Between nodes: 0 1 4
0 2 5
0 3 6
1 2 0
1 3 7
2 3 5
cost adjacency matrix
is:
0 1990 4 5
6
1 4
1931 6
7
2 5
0 11780 5
3 6
7 5
-2895
enter the src node:
2
enter dest. Node:
1
shortest path is:
2->0->1
cost of path =9.
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|
.
|
RSA
#include<stdio.h> #include<conio.h> #include<string.h> int n,b[10],k,c=3,d; void binary(int); void
main() { char ch[20],c,y[20]; int i=0,j,nc,t,x[20],z,phi,p,q; clrscr(); printf("\n
enter the text"); do { c=getchar(); ch[i++]=c; } while(c!='\n'); nc=i-1; printf("enter
p ,q"); scanf("%d%d",&p,&q); p=prime(p); q=prime(q); if(p==q) { p++; p=prime(p); } printf("\n
prime no p=%d,q=%d",p,q); n=p*q; phi=(p-1)*(p-1); if(e>1&&e<phi) while(gcd(phi,e)!=1) e++; for(d=1;d<phi;d++) if((d*e)%phi==1) break; printf("\n
public key:{e,n}={%d,%d}",e,n); printf("\n private key:{d,n}={%d,%d}",d,n); printf("after encryption:"); for(i=0,t=0;t<n;t++,i++) { x[i]=ch[t]-96; z=rsa(x[i]); y[i]=z+96; } printf("\n
after decryption"); for(i=0;i<nc;i++) printf("%c",y[i]); getch(); } int rsa(int m); { int
c,pl; char ci; binary(e); c=modular(m,b); ci=c+96; printf("%c",ci); binary(d); pl=modular(c,b); return
pl; } int prime(int x) { int i,j=0; for(i=2;i<x;i++) if(x%i==0) j=1; if(j!=1) return
x; else return prime(++x); } int gcd(int x,int y) { int temp; if(x<y) { temp=x; x=y; y=temp; } while(y!=0) { temp=x%y; x=y; y=temp; } return
x; } void binary(int x) { int l; k=0; while(x!=1) { l=x/2; b[k]=x%2; k++; x=l; } b[k]=x; } int
modular(int a,int b[]) { int c=0,d=1,i; for(i=k;i>=0;i--) { c=2*c; d=(d*d)%n; if(b[i]==1) { c=c+1; d=(d*a)%n; } } return
d; }
OUTPUT:
Enter the plain
text : abcde
Enter p and q :
2 11
Public key:{e,n}
= {3,22}
Private key:{d,n}
= {7,22}
After encryption
: aheto
After decryption
: abcde
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.
|
DISTANCE VECTOR ROUTING ALG
#include<stdio.h>
#include<conio.h>
#define INFINITY 1000
void main()
{
FILE *fp;
int
a[20][20],b[20][20],d[20[20];
int i,j,n,k,s,u,v;
clrscr();
printf("enter the number of nodes:");
scanf("%d",&n);
printf("enter
the costs:");
for(i=0;i<n;i++)
for(j=i+1;j<n;j++)
{
printf("%d,%d",i,j);
scanf("%d",&d[i][j]);
a[j][i]=d[i][j];
}
printf("\n
cost adjacency matrixis:\n");
printf(" ");
for(i=0;i<n;i++)
printf("%d",i);
printf("\n...\n");
for(i=0;i<n;i++)
{
printf("%d",i);
for(j=0;j<n;j++)
{
printf("%d",a[i][j]);
}
printf("\n");
}
for(i=0;i<n;i++)
for(j=0;j<n;j++)
{
b[i][j]=a[i][j];
if(!a[i][j]&&(i!=j))
b[i][j]=INFINITY;
}
for(k=0;k<n;k++)
for(i=0;i<n;i++)
for(j=0;j<n;j++)
if(b[i][k]&&b[k][j])
if(b[i][k]+b[k][j]<b[i][j])
b[i][j]=b[i][k]+b[k][j];
fp=fopen("c:\rinf.c","w");
fprintf(fp,"source\tdestination\tcost\n");
fprintf(fp,".......\t.....\t....\n");
for(i=0;i<n;i++)
for(j=0;j<n;j++)
if(i!=j)
fprintf(fp,"%d\t
%d\t %d\n",i,j,b[i][j]);
fclose(fp);
printf("\n enter the source node");
label : scanf("%d",&s);
if(s<0||s>=n)
{
printf("please
enter the valid source node");
goto label;
}
fp=fopen("c:\rinf.c","r");
printf("\n
routing table at node %d is ",s);
printf("\n source \t destination \t cost \t \n");
for(i=0;i<n;i++)
for(j=0;j<n;j++)
{
fscan(fp,"%d%d%d",&i,&j,&b[i][j]);
if(i==s&&i!=j)
fprintf(stdout,"%d%d%d",i,j,b[i][j]);
}
fclose(fp);
getch();
}
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.
|
COUNT
#include<stdio.h>
#include<conio.h>
void main()
{
char a[40],b[40],ch;
int i=0,j=0,m,n,cnt=0,l;
printf("enter
input stream");
do
{
ch=getchar();
a[i++]=ch;
}
while(ch!='\n');
n=i-1;
l=n;
printf("enter
the frame size");
scanf("%d",&m);
for(i=0;i<n;i++)
{
cnt=cnt+1;
printf("\n
frame %d",cnt);
if(l>=m)
{
printf("%d",m);
l=l-m;
}
else
printf("%d",l);
for(j=i;j<i+m&&j<n;j++)
printf("%c",a[j]);
printf("\n");
}
getch();
}
OUTPUT:
Enter input stream : computernetworks
Enter the frame size : 3
frame
1 3com
frame
2 3omp
frame
3 3mpu
frame
4 3put
frame
5 3ute
frame
6 1ter
frame
7 1ern
frame
8 1rne
frame
9 1net
frame
10 1etw
frame
11 1two
frame
12 1wor
frame
13 1ork
frame
14 1rks
frame
15 1ks
frame
16 1s
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