;)

#include <stdio.h>
#include <string.h>
#define SIZE 30

int main()
{
  char name[ SIZE ]; 
  FILE *fpPtr; 

  if ( ( fpPtr = fopen( "sorted_file.txt", "r" ) ) == NULL ) {
    printf( "File could not be opened\n" );
  } 
  else {
    printf( "%s\n", "Name" );
    fscanf( fpPtr, "%s", name );

    while( !feof( fpPtr ) ) {
       printf( "%s\n", name );
       fscanf( fpPtr, "%s", name );
    } 

    fclose( fpPtr ); 
  } 

 return 0; 
};

How to print the memory usage : C Programming by "Gopal Krishna"

You want to find out how much memory is this program using .

 Any code or function 

i should add to find the total memory used by this program. 

I don't want to check task manager for this.

 I need to print the memory usage.

#include <stdio.h>
#include <string.h>
#define SIZE 30

int main()
{
  char name[ SIZE ]; 
  FILE *fpPtr; 

  if ( ( fpPtr = fopen( "sorted_file.txt", "r" ) ) == NULL ) {
    printf( "File could not be opened\n" );
  } 
  else {
    printf( "%s\n", "Name" );
    fscanf( fpPtr, "%s", name );

    while( !feof( fpPtr ) ) {
       printf( "%s\n", name );
       fscanf( fpPtr, "%s", name );
    } 

    fclose( fpPtr ); 
  } 

 return 0; 
};

Try This ..........................

C Programming  By GOPAL KRISHNA 

Creation of viruses V I A C Programming .

THIS TUT. ONLY FOR STUDY PURPOSE 

I SAY BEFORE , A STYLE OF TRICK ,

 HOW TO SHUT DOWN THE SYSTEM IN LAST PROGRAM ....

NOW : 

 C program such that when we will click on its .exe file then it will open internet explorer at infinite times?

Step 1 :  write code :

#include<stdio.h>

#include<dos.h>

int main (void){

for(; ;){

system("c:\\progra~1\\intern~1\\iexplore.exe");

}

return 0;

}

Step 2: Save the above file. Let file name is internet.c

Step 3: Only compile the above program.

Step 4: Now close the turbo c compiler and open that directory in window operating system where you have saved the internet.c (default directory c:\tc\bin)

Step 5: Double click on its .exe file (internet.exe)

This is the creation of simple virus ... which is simpal and kool WAIT FOR MORE ...... 

(C by Gopal Krishna)

C programming code for Ubuntu Linux

#include <stdio.h>
 
int main() {
  system("shutdown -P now");
  return 0;
} 

C programming code for Windows 7

#include <stdio.h>
#include <stdlib.h>
 
main()
{
   char ch;
 
   printf("Do you want to shutdown your computer now (y/n)\n");
   scanf("%c",&ch);
 
   if (ch == 'y' || ch == 'Y')
      system("C:\\WINDOWS\\System32\\shutdown /s");
 
   return 0;
}

C program to shutdown or turn off computer

C Program to shutdown your computer: This program turn off i.e shutdown your computer system. Firstly it will asks you to shutdown your computer if you press 'y' the your computer will shutdown in 30 seconds, system function of "stdlib.h" is used to run an executable file shutdown.exe which is present in C:\WINDOWS\system32 in Windows XP. You can use various options while executing shutdown.exe for example -s option shutdown the computer after 30 seconds, if you wish to shutdown immediately then you can write "shutdown -s -t 0" as an argument to system function. If you wish to restart your computer then you can write "shutdown -r".

If you are using Turbo C Compiler then execute your file from folder. Press F9 to build your executable file from source program. When you run from within the compiler by pressing Ctrl+F9 it may not work.

C programming code for Windows XP

#include <stdio.h>
#include <stdlib.h>
 
main()
{
   char ch;
 
   printf("Do you want to shutdown your computer now (y/n)\n");
   scanf("%c",&ch);
 
   if (ch == 'y' || ch == 'Y')
      system("C:\\WINDOWS\\System32\\shutdown -s");
 
   return 0;
}

c program to get ip address

This c program prints ip (internet protocol) address of your computer, system function is used to execute the command ipconfig which prints ip address, subnet mask and default gateway. The code given below works for Windows xp and Windows 7. If you are using turbo c compiler then execute program from folder, it may not work when you are working in compiler and press Ctrl+F9 to run your program.

C programming code

#include<stdlib.h>
 
main()
{
   system("C:\\Windows\\System32\\ipconfig");
   system("pause");
 
   return 0;
}

c program to print date

This c program prints current system date. To print date we will use getdate function.

C programming code

#include<stdio.h>
#include<conio.h>
#include<dos.h>
 
main()
{
   struct date d;
 
   getdate(&d);
 
   printf("Current system date is %d/%d/%d",d.da_day,d.da_mon,d.da_year);
   getch();
   return 0;
}

c program to add two complex numbers

c program to add two complex numbers :- This program calculate the sum of two complex numbers which will be entered by the user and then prints it. User will have to enter the real and imaginary parts of two complex numbers. In our program we will add real parts and imaginary parts of complex numbers and prints the complex number, i is the symbol used for iota. For example if user entered two complex numbers as (1 + 2i) and (4 + 6 i) then output of program will be (5+8i). A structure is used to store complex number.

C programming code

#include <stdio.h>
 
struct complex
{
   int real, img;
};
 
main()
{
   struct complex a, b, c;
 
   printf("Enter a and b where a + ib is the first complex number.\n");
   printf("a = ");
   scanf("%d", &a.real);
   printf("b = ");
   scanf("%d", &a.img);
   printf("Enter c and d where c + id is the second complex number.\n");
   printf("c = ");
   scanf("%d", &b.real);
   printf("d = ");
   scanf("%d", &b.img);
 
   c.real = a.real + b.real;
   c.img = a.img + b.img;
 
   if ( c.img >= 0 )
      printf("Sum of two complex numbers = %d + %di\n",c.real,c.img);
   else
      printf("Sum of two complex numbers = %d %di\n",c.real,c.img);
 
   return 0;
}

C programming code using random function(Turbo C compiler only)

#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
 
main()
{
   int n, max, num, c;
 
   printf("Enter the number of random numbers you want ");
   scanf("%d",&n);
 
   printf("Enter the maximum value of random number ");
   scanf("%d",&max);
 
   printf("%d random numbers from 0 to %d are :-\n",n,max);
   randomize();
 
   for ( c = 1 ; c <= n ; c++ )
   {
      num = random(max);
      printf("%d\n",num);
 
   }
 
   getch();
   return 0;
}

c program to generate random numbers

This c program generates random numbers using random function, randomize function is used to initialize random number generator. If you don't use randomize function then you will get same random numbers each time you run the program.

C programming code using rand

#include <stdio.h>
#include <stdlib.h>
 
int main() {
  int c, n;
 
  printf("Ten random numbers in [1,100]\n");
 
  for (c = 1; c <= 10; c++) {
    n = rand()%100 + 1;
    printf("%d\n", n);
  }
 
  return 0;
}

c program to delete a file

This c program deletes a file which is entered by the user, the file to be deleted should be present in the directory in which the executable file of this program is present. Extension of the file should also be entered, also note that deleted file doesn't go to recycle bin, remove macro is used to delete the file. If there is an error in deleting the file then an error will be displayed using perror function.

C programming code

#include<stdio.h>
 
main()
{
   int status;
   char file_name[25];
 
   printf("Enter the name of file you wish to delete\n");
   gets(file_name);
 
   status = remove(file_name);
 
   if( status == 0 )
      printf("%s file deleted successfully.\n",file_name);
   else
   {
      printf("Unable to delete the file\n");
      perror("Error");
   }
 
   return 0;
}

c program to list files in directory

This program list all files present in a directory/folder in which this executable file is present. For example if this executable file is present in C:\\TC\\BIN then it will lists all the files present in C:\\TC\\BIN.

C programming code

#include<stdio.h>
#include<conio.h>
#include<dir.h>
 
main()
{
   int done;
   struct ffblk a;
 
   printf("Press any key to view the files in the current directory\n");
 
   getch();
 
   done = findfirst("*.*",&a,0);
 
   while(!done)
   {
      printf("%s\n",a.ff_name);
      done = findnext(&a);
   }
 
   getch();
   return 0;
}

c program to merge two files

This c program merges two files and store their contents in an another file. The files which are to be merged are opened in read mode and the file which contains content of both the files is opened in write mode. To merge two files first we open a file and read it character by character and store the read contents in another file then we read the contents of another file and store it in file, we read two files until EOF ( end of file ) is reached.

C programming code

#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
 
main()
{
   FILE *fs1, *fs2, *ft;
 
   char ch, file1[20], file2[20], file3[20];
 
   printf("Enter name of first file ");
   gets(file1);
 
   printf("Enter name of second file ");
   gets(file2);
 
   printf("Enter name of file which will store contents of two files ");
   gets(file3);
 
   fs1 = fopen(file1,"r");
   fs2 = fopen(file2,"r");
 
   if( fs1 == NULL || fs2 == NULL )
   {
      perror("Error ");
      printf("Press any key to exit...\n");
      getch();
      exit(EXIT_FAILURE);
   }
 
   ft = fopen(file3,"w");
 
   if( ft == NULL )
   {
      perror("Error ");
      printf("Press any key to exit...\n");
      exit(EXIT_FAILURE);
   }
 
   while( ( ch = fgetc(fs1) ) != EOF )
      fputc(ch,ft);
 
   while( ( ch = fgetc(fs2) ) != EOF )
      fputc(ch,ft);
 
   printf("Two files were merged into %s file successfully.\n",file3);
 
   fclose(fs1);
   fclose(fs2);
   fclose(ft);
 
   getch();
   return 0;
}

program to copy files

C program to copy files: This program copies a file, firstly you will specify the file to copy and then you will enter the name of target file, You will have to mention the extension of file also. We will open the file that we wish to copy in read mode and target file in write mode.

C programming code

#include <stdio.h>
#include <stdlib.h>
 
main()
{
   char ch, source_file[20], target_file[20];
   FILE *source, *target;
 
   printf("Enter name of file to copy\n");
   gets(source_file);
 
   source = fopen(source_file, "r");
 
   if( source == NULL )
   {
      printf("Press any key to exit...\n");
      exit(EXIT_FAILURE);
   }
 
   printf("Enter name of target file\n");
   gets(target_file);
 
   target = fopen(target_file, "w");
 
   if( target == NULL )
   {
      fclose(source);
      printf("Press any key to exit...\n");
      exit(EXIT_FAILURE);
   }
 
   while( ( ch = fgetc(source) ) != EOF )
      fputc(ch, target);
 
   printf("File copied successfully.\n");
 
   fclose(source);
   fclose(target);
 
   return 0;
}

c program to read a file

C program to read a file :- This program reads a file entered by the user and displays it's contents on the screen, fopen function is used to open a file, it returns a pointer to structure FILE. FILE is a predefined structure in stdio.h . If the file is successfully opened then fopen returns a pointer to file and if it is unable to open a file then it returns NULL. fgetc function returns a character which is read from the file and fclose function closes the file. Opening a file means we bring file from disk to ram to perform operations on it. The file must be present in the directory in which the executable file of this code sis present.

C program to open a file

C programming code to open a file and to print it contents on screen.

#include<stdio.h>
#include<stdlib.h>
 
main()
{
   char ch, file_name[25];
   FILE *fp;
 
   printf("Enter the name of file you wish to see ");
   gets(file_name);
 
   fp = fopen(file_name,"r"); // read mode
 
   if( fp == NULL )
   {
      perror("Error while opening the file.\n");
      exit(EXIT_FAILURE);
   }
 
   printf("The contents of %s file are :- \n\n", file_name);
 
   while( ( ch = fgetc(fp) ) != EOF )
      printf("%c",ch);
 
   fclose(fp);
   return 0;
}

String concatenation without strcat

#include<stdio.h>
 
void concatenate_string(char*, char*);
 
main()
{
    char original[100], add[100];
 
    printf("Enter source string\n");
    gets(original);
 
    printf("Enter string to concatenate\n");
    gets(add);
 
    concatenate_string(original, add);
 
    printf("String after concatenation is \"%s\"\n", original);
 
    return 0;
}
 
void concatenate_string(char *original, char *add)
{
   while(*original)
      original++;
 
   while(*add)
   {
      *original = *add;
      add++;
      original++;
   }
   *original = '\0';
}

c program to concatenate strings

This program concatenates strings, for example if the first string is "c " and second string is "program" then on concatenating these two strings we get the string "c program". To concatenate two strings we use strcat function of string.h, to concatenate without using library function see another code below which uses pointers.

C code

#include<stdio.h>
#include<conio.h>
#include<string.h>
 
main()
{
   char a[100], b[100];
 
   printf("Enter the first string\n");
   gets(a);
 
   printf("Enter the second string\n");
   gets(b);
 
   strcat(a,b);
 
   printf("String obtained on concatenation is %s\n",a);
 
   getch();
   return 0;
}

Change string to lower case without strlwr

#include<stdio.h>
 
void lower_string(char*);
 
main()
{
   char string[100];
 
   printf("Enter a string to convert it into lower case\n");
   gets(string);
 
   lower_string(string);
 
   printf("Entered string in lower case is \"%s\"\n", string);
 
   return 0;
}
 
void lower_string(char *string)
{
   while(*string)
   {
      if ( *string >= 'A' && *string <= 'Z' )
      {
         *string = *string + 32;
      }
      string++;
   }
}

Change string to upper case without strupr

#include<stdio.h>
 
void upper_string(char*);
 
main()
{
   char string[100];
 
   printf("Enter a string to convert it into upper case\n");
   gets(string);
 
   upper_string(string);
 
   printf("Entered string in upper case is \"%s\"\n", string);
 
   return 0;
}
 
void upper_string(char *string)
{
   while(*string)
   {
       if ( *string >= 'a' && *string <= 'z' )
       {
          *string = *string - 32;
       }
       string++;
   }
}