Program without using function main()

“ANSI C” Program without using main function

#include<stdio.h>

#include<conio.h>

#define decode(s,t,u,m,p,e,d) m##s##u##t

#define begin decode(a,n,i,m,a,t,e)

int begin()

{

     clrscr();

     printf("hello..friends");

     getch();

}

How..?

 we are using preprocessor directive #define with arguments.The ‘##’

 operator is called the token pasting or token merging operator.That is

 we can merge two or more characters with it.

NOTE: A Preprocessor is program which processes the source code before compilation.

Look at the second line of program-

#define decode(s,t,u,m,p,e,d) m##s##u##t

What is the preprocessor doing here…? The macro decode(s,t,u,m,p,e,d) is being

 expanded as “msut” (The ## operator merges m,s,u & t into msut).The

 logic is when you pass (s,t,u,m,p,e,d) as argument it merges the

 4th,1st,3rd & the 2nd characters(tokens).

Now look at the third line of the program-

#define begin decode(a,n,i,m,a,t,e)

Here the preprocessor replaces the macro “begin” with the expansion

 decode(a,n,i,m,a,t,e).According to the macro definition in the previous

 line the argument must be expanded so that the 4th,1st,3rd & the

 Second characters must be merged .In the argument (a,n,i,m,a,t,e)

4th,1st,3rd & the second characters are ‘m’,'a’,'i’ & ‘n’.

So the third line “int begin()” is replaced by “int main()” by the

 preprocessor before the program is passed on for the compiler. That’s

 it…The bottom line is there can never exist a C program

 without a main() function we are using the processor directive to intelligently replace the word begin” by  “main” .

Airtel Music Using C

Program:
//AIRTEL MUSIC USING 'C'
//airtel.c
#include<dos.h>
#include<stdio.h>
#include<conio.h>
int main(void)
{
float A,Bb,D,G,F;
A = 440;
G = 780;
Bb = 461;
D = 586;
F = 687;
int i,j;
for(i=0;i<=2;i++)
{
sound(G);delay(500);nosound();
sound(G);delay(250);nosound();
sound(G);delay(250);nosound();
sound(G);delay(500);nosound();
sound(2*D);delay(500);nosound();
sound(2*A);delay(250);nosound();
sound(2*Bb);delay(250);nosound();
sound(2*A);delay(250);nosound();
sound(G);delay(250);nosound();
sound(F);delay(500);nosound();
sound(2*A);delay(500);nosound();
sound(G);delay(250);nosound();
sound(2*A);delay(250);nosound();
sound(G);delay(250);nosound();
sound(F);delay(250);
sound(G);delay(250);
sound(2*A);delay(250);
sound(2*Bb);delay(500);
sound(2*A);delay(500);
sound(G);delay(250);
sound(F);delay(250);
sound(D);delay(500);nosound();
}
for(j=0;j<=2;j++)
{
sound(2*A);delay(250);nosound();
sound(G);delay(250);nosound();
sound(F);delay(250);
sound(G);delay(250);
sound(2*A);delay(250);
sound(2*Bb);delay(500);
sound(2*A);delay(500);
sound(G);delay(250);
sound(F);delay(250);
sound(D);delay(500);nosound();
}
getch();
return 0;
}

Output:

 <Insert headphone and listen the music>

Print all values passed by commandline arguments in C++

Program:

//disp.cpp
#include<iostream.h>    
#include<conio.h>
int main(int args,char *argv[])
{
for(int i=0;i<args;i++)
cout<<"\n"<<argv[i];
getch();
return 0;
}

Output:

disp.c Hai hello

Hai
hello

Print All values passed by commandline arguments in C

Program:

//disp.c
#include<stdio.h>         //print all values passed by commandline arguments
#include<conio.h>         //TESTED
int main(int args,char *argv[])
{
for(int i=0;i<args;i++)
printf("\n%s",argv[i]);
getch();
return 0;
}

Output:

disp.c Hai hello

Hai
hello 

Adding 2 numbers in Command line arguments

Program:

//ADD.CPP
#include<iostream.h>
#include<conio.h>                    
#include<stdlib.h>                    
void main(int argc , char * argv[])
{
    clrscr();
    int i,sum=0;
    if(argc!=3)
    {
      cout<<"\nYou have forget to type numbers";
      getch();
      exit(1);
    }
    cout<<"\nThe SUM is:";
    for(i=1;i<argc;i++)
    sum = sum + atoi(argv[i]);
    cout<<sum;
    getch();
}

Output:

[Ctrl+F9 does'nt work here]
Navigate File ---> DOS shell --->Type Program name . extention (ie. ADD.CPP 20 30)

ADD.CPP 20 30
The SUM is:50

Remove Duplicate Entries in an Array

Program:
#include<stdio.h>
#include<conio.h>
int main(void)
{
int a[20],i,j,k,n;
clrscr();
printf("\nEnter Array size : ");
scanf("%d",&n);
printf("\nEnter Numbers :\n ");
for(i=0;i<n;i++)
  scanf("%d",&a[i]);
clrscr();
printf("\nOriginal Array is : \n");
for(i=0;i<n;i++)
  printf("\n %d",a[i]);
printf("\nUpdated Array is  :\n ");
for(i=0;i<n;i++)
{
for(j=i+1;j<n;)
    {
       if(a[j]==a[i])
       {
  for(k=j;k<n;k++)
      a[k]=a[k+1];
   n--;
       }
       else
  j++;
    }
}
for(i=0;i<n;i++)
    printf("\n%d ",a[i]);
getch();
return 0;
}

Output:
Enter Array size : 5
Enter Numbers:
2
4
5
5
6
Original Array is:
2
4
5
5
6
Updated Array is:
2
4
5
6

Program to print it's Own Source code

Program:
#include<stdio.h>    
#include<conio.h>    
int main()
{
clrscr();
FILE *fp;
char c;
fp = fopen(__FILE__,"r");
do
{
c= getc(fp);
putchar(c);
}
while(c!=EOF);
fclose(fp);
getch();
return 0;
}

Output:

#include<stdio.h>  
#include<conio.h>    
int main()
{
clrscr();
FILE *fp;
char c;
fp = fopen(__FILE__,"r");
do
{
c= getc(fp);
putchar(c);
}
while(c!=EOF);
fclose(fp);
getch();
return 0;
}

String Sort

Program:
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<conio.h>
int main()
{
     clrscr();
    char *str[5],*temp;
    int i,j,n;
    printf("\nHow many names do you want to sort:");
    scanf("%d",&n);
    for(i=0;i<n;i++)
    {
        printf("\nEnter the name %d: ",i);
        flushall();
        gets(str[i]);
    }
    for(i=0;i<n;i++)
    {
     for(j=0;j<n-1;j++)
     {
       if(strcmp(str[j],str[j+1])>0)
         {
         strcpy(temp,str[j]);
         strcpy(str[j],str[j+1]);
         strcpy(str[j+1],temp);
         }
     }
    }
    printf("\nSorted List : \n");
    flushall();
    for(i=0;i<n;i++)
        puts(str[i]);
getch();
    return(0);
}

Output:
How many names do you want to sort:5
Enter the name 0:Google
Enter the name 1:Bing
Enter the name 2:Amazon
Enter the name 3:Facebook
Enter the name 4:Twitter
Sorted List :
Amazon
Bing
Facebook
Google
Twitter

Program for converting Roman letter into Decimal number

Program:
#include<stdio.h>
#include<string.h>
#include<conio.h>
int digitValue(char);
int main()
{
clrscr();
char roman_Number[1000];
int i=0;
long int number =0;
printf("\nEnter roman letter: ");
scanf("%s",roman_Number);
while(roman_Number[i])
{
if(digitValue(roman_Number[i]) < 0)
{
printf("Invalid roman digit : %c",roman_Number[i]);
return 0;
}
if((strlen(roman_Number) -i) > 2)
{
if(digitValue(roman_Number[i]) < digitValue(roman_Number[i+2])){
printf("Invalid roman number");
return 0;
}
}
if(digitValue(roman_Number[i]) >= digitValue(roman_Number[i+1]))
number = number + digitValue(roman_Number[i]);
else
{
number = number + (digitValue(roman_Number[i+1]) - digitValue(roman_Number[i]));
i++;
}
i++;
    }
    printf("\nEqual decimal value is : %ld",number);
    getch();
    return 0;
}
int digitValue(char c)
{
int value=0;
switch(c)
{
case 'I': value = 1; break;
case 'V': value = 5; break;
case 'X': value = 10; break;
case 'L': value = 50; break;
case 'C': value = 100; break;
case 'D': value = 500; break;
case 'M': value = 1000; break;
case '\0': value = 0; break;
default: value = -1;
}
return value;
}

Output:

Enter roman letter : VII
Equal decimal value is : 7 

Program for Adding two binary numbers

Program:
#include<stdio.h>   //TESTED
#include<conio.h>
int main()
{
clrscr();
    long int binary1,binary2;
    int i=0,remainder = 0,sum[20];
printf("\nEnter binary number 2: ");
scanf("%ld",&binary1);
    printf("\nEnter binary number 2: ");
    scanf("%ld",&binary2);
while(binary1!=0||binary2!=0)
{
        sum[i++] =  (binary1 %10 + binary2 %10 + remainder ) % 2;
        remainder = (binary1 %10 + binary2 %10 + remainder ) / 2;
        binary1 = binary1/10;
        binary2 = binary2/10;
}
if(remainder!=0)
        sum[i++] = remainder;
        --i;
    printf("\nSum of two binary numbers: ");
    while(i>=0)
        printf("%d",sum[i--]);
    getch();
    return 0;
}

Output:
Enter binary number 1: 10
Enter binary number 2: 11
Sum of two binary numbers:101

Convert Decimal Into Hexadecimal

Program:

#include<stdio.h>
#include<conio.h> //tested
int main()
{
    clrscr();
    long int decimalNumber,remainder,quotient;
    int i=1,j,temp;
    char hexadecimalNumber[100];
    printf("Enter any decimal number: ");
    scanf("%ld",&decimalNumber);
    quotient = decimalNumber;
    while(quotient!=0)
    {
         temp = quotient % 16;
         //To convert integer into character
         if( temp < 10)
           temp =temp + 48;
        else
          temp = temp + 55;
        hexadecimalNumber[i++]= temp;
       quotient = quotient / 16;
  }

    printf("Equivalent hexadecimal value of decimal number %d: ",decimalNumber);
    for(j = i -1 ;j> 0;j--)
    printf("%c",hexadecimalNumber[j]);
    getch();
    return 0;
}

Output:
Enter any decimal number:16
Equivalent hexadecimal value of decimal number 16 : f

Pattern Printing (Alphabetic Triangle)

Program:

#include<stdio.h>
#include<conio.h>
int main()
{
    clrscr();
    char i,k,m,h=71;
    int g=1;
    float j;
    for(i=71;i>=65;i--)
    {
        for(m=65;m<=i;m++)
        {
            printf("%c",m);
        }
        for(j=2;j<=g;j++)
        {
            printf("__"); // Two Spaces
        }
        g++;
        printf("\b");
        for(k=h;k>=65;k--)
        {
            printf("%c",k);
        }
        h--;
        printf("\n");
    }
    getch();
    return 0;
}



output:
ABCDEFGFEDCBA
ABCDEF_FEDCBA
ABCDE___EDCBA
ABCD_____DCBA
ABC_______CBA
AB_________BA
A___________A

Text Masking Using C

#include<stdio.h>
#include<conio.h>
char pw[25],ch;
int i;
void main()
{
     clrscr();
     puts(“Enter password”);
     while(1)
     {
          if(i<0)
          i=0;
         ch=getch();
          if(ch==13)
          break; /*13 is ASCII value of ENTER*/
          if(ch==8) /*ASCII value of BACKSPACE*/
          {
               putch(‘\b’);
               putch(NULL);
               putch(‘\b’);
               –i;
               continue;
          }
          pw[i++]=ch;
          ch=’*';
          putch(ch);
     }
     pw[i]=’\0';
     printf(“\n\n%s”,pw);
     getch();
}

Make folder using C

#include <stdio.h>
#include <conio.h>
#include <process.h>
#include <dir.h>
#define DIRNAME "c:\\testdir"
int main(void)
{
   int stat;
   stat = mkdir(DIRNAME);
   if (!stat)
      printf("Directory created\n");
   else
   {
      printf("Unable to create directory\n");
      exit(1);
   }
   getch();
   system("dir/p");
   getch();
   stat = rmdir(DIRNAME);
    if (!stat)
      printf("\nDirectory deleted\n");
   else
   {
      perror("\nUnable to delete directory\n");
      exit(1);
   }
   return 0;
}

"FLAMES" Using C++

#include<iostream.h>
#include<conio.h>
#include<string.h>
int main()
{
     char n1[20],n2[20],a[20],b[20];
     int i,j,tot=0;
     cout<<"\n Enter the boy name  : ";
     cin>>a;
     cout<<"\n Enter the girl name : ";
     cin>>b;
     cout<<endl;
     strcpy(n1,a);
     strcpy(n2,b);
     i=strlen(a);
     j=strlen(b);
     tot=i+j;
     for(i=0;a[i]!=NULL;i++)
    {
          for(j=0;b[j]!=NULL;j++)
          {
               if(a[i]==b[j]) //for checking same characters
              {
                   tot=tot-2;
                   b[j]='*';  //to avoid duplication
                   break;
               }
          }
     }
cout<<"\n count = "<<tot<<endl;
if(tot == 2 ||tot== 4 || tot==7 ||tot==9 )
cout<<   n1 << " and " << n2 << " are Enemy";
else if( tot == 3 ||tot==5 || tot==14 ||tot==16 || tot==18 )
cout<<   n1 << " and " << n2 << " are Friends";
else if( tot == 8 || tot==12 || tot==17)
cout<<   n1 << " and " << n2 << " in Affection";
else if( tot == 10)
cout<<   n1 << " and " << n2 << " Love";
else if( tot == 6 || tot==11 || tot==15)
cout<<   n1 << " and " << n2 << " will arriage";
else
cout<<   n1 << " and " << n2 << " are SweetHearts";
getch();
return 0;
}