Here we create a PHP script, name it “download.php” and copy/paste the following code:

<?php
 
ignore_user_abort(true);
set_time_limit(0); // disable the time limit for this script
 
$path = "/absolute_path_to_your_files/"; // change the path to fit your websites document structure
 
$dl_file = preg_replace("([^\w\s\d\-_~,;:\[\]\(\).]|[\.]{2,})", '', $_GET['download_file']); // simple file name validation
$dl_file = filter_var($dl_file, FILTER_SANITIZE_URL); // Remove (more) invalid characters
$fullPath = $path.$dl_file;
 
if ($fd = fopen ($fullPath, "r")) {
    $fsize = filesize($fullPath);
    $path_parts = pathinfo($fullPath);
    $ext = strtolower($path_parts["extension"]);
    switch ($ext) {
        case "pdf":
        header("Content-type: application/pdf");
        header("Content-Disposition: attachment; filename=\"".$path_parts["basename"]."\""); // use 'attachment' to force a file download
        break;
        // add more headers for other content types here
        default;
        header("Content-type: application/octet-stream");
        header("Content-Disposition: filename=\"".$path_parts["basename"]."\"");
        break;
    }
    header("Content-length: $fsize");
    header("Cache-control: private"); //use this to open files directly
    while(!feof($fd)) {
        $buffer = fread($fd, 2048);
        echo $buffer;
    }
}
fclose ($fd);
exit;

Create on your webpage links for each file which attacks in a password protected directory or in a directory above the website root directory.

In our example use the following download URL:

<a href="https://mydomain.com/download.php?download_file=some_file.pdf">PHP download file</a>

Function main() {
  integer a = 5, b = 7
  Switch(a) {
    Case 5: print "I am 5"
    Break
    Case b: print "I am not 5"
    Break
    Default: print "I am different"
  }
}

Answer : D. Error

Sample Code

#include <stdio.h> 
// Recursive function to return gcd of a and b
int gcd(int a, int b)
{
// Everything divides 0
    if (a == 0 || b == 0)
        return 0;
// Base case
    if (a == b)
        return a;
// a is greater
    if (a > b)
        return gcd(a-b, b);
    return gcd(a, b-a);
}
// Function to return LCM of two numbers
int lcm(int a, int b)
{
    return (a*b)/gcd(a, b);
}
// Driver program to test above function
int main()
{
    int a = 10, b = 28;
    printf("LCM of %d and %d is %d ", a, b, lcm(a, b));
    return 0;
}

Output

LCM of 10 and 28 is 140

In this example, we have to count digits, spaces, special characters and alphabets using C program.

#include <stdio.h>
 
int main()
{
    char    str[100];
    int countDigits,countAlphabet,countSpecialChar,countSpaces;
    int counter;
 
    //assign all counters to zero
    countDigits=countAlphabet=countSpecialChar=countSpaces=0;
 
    printf("Enter a string: ");
    gets(str);
 
    for(counter=0;str[counter]!=NULL;counter++)
    {
 
        if(str[counter]>='0' && str[counter]<='9')
            countDigits++;
        else if((str[counter]>='A' && str[counter]<='Z')||(str[counter]>='a' && str[counter]<='z'))
            countAlphabet++;
        else if(str[counter]==' ')
            countSpaces++;
        else
            countSpecialChar++;
    }
 
    printf("\nDigits: %d \nAlphabets: %d \nSpaces: %d \nSpecial Characters: %d",countDigits,countAlphabet,countSpaces,countSpecialChar);
 
    return 0;
}

Output :

Enter a string: wikitechy, 789@#%12.

Digits: 5
Alphabets: 9
Spaces: 1
Special Characters: 5

#include<stdio.h>
#include<conio.h>
void main()
{
	clrscr();
	long int i=0;
	char binarynum[100], hexdec[100];
	printf("Enter Hexadecimal Value : ");
	scanf("%s",hexdec);
	printf("\nEqual Binary value is : ");
	while(hexdec[i])
	{
		switch(hexdec[i])
		{
			case '0' : printf("0000");
				break;
			case '1' : printf("0001");
				break;
			case '2' : printf("0010");
				break;
			case '3' : printf("0011");
				break;
			case '4' : printf("0100");
				break;
			case '5' : printf("0101");
				break;
			case '6' : printf("0110");
				break;
			case '7' : printf("0111");
				break;
			case '8' : printf("1000");
				break;
			case '9' : printf("1001");
				break;
			case 'A' : printf("1010");
				break;
			case 'B' : printf("1011");
				break;
			case 'C' : printf("1100");
				break;
			case 'D' : printf("1101");
				break;
			case 'E' : printf("1110");
				break;
			case 'F' : printf("1111");
				break;
			case 'a' : printf("1010");
				break;
			case 'b' : printf("1011");
				break;
			case 'c' : printf("1100");
				break;
			case 'd' : printf("1101");
				break;
			case 'e' : printf("1110");
				break;
			case 'f' : printf("1111");
				break;
			default : printf("\nInvalid hexadecimal digit %c",hexdec[i]);
		}
		i++;
	}
	getch();
}

Enter Hexadecimal Value : AB1c 
Equal Binary value is : 1010101100011100

main () 
  {
  char *p1="Name"; 
  char *p2; 
  p2=(char *)malloc(20); 
  while(*p2++=*p1++); 
  printf("%s\n",p2); 
  } 

Answer : NULL

main()
{
int x=20,y=35;
x = y++ + x++;
y = ++y + ++x;
printf("%d %d\n",x,y);
} ? 

While calculating the x value, x & y values are post incremented. So, the values of x & y are added and then incremented i.e. x=56, y=36

While calculating the y value, x & y values are preincremented, so x & y values are incremented and then added i.e x=57, y=37.

{ x=y++ + x++; } equal to

x=y+x;//35+20
x++; //56
y++; //36
}

y=++y + ++x; is equal to

++y;//37
++x;//57
y=y+x;//37+57
}

Output:

x=57
 y=94