How to generate random numbers in C

February 19, 2015

To generate a random number in C you can use the snippet below.

Sample C

#include <time.h>
#include <stdlib.h>

srand(time(NULL));
int r = rand();

February 11, 2015

To Set / Clear and Toggle a single bit in C++ see the methods below.

Use the bitwise OR operator (|) to set a bit.

number |= 1 << x;

Use the bitwise AND operator (&) to clear a bit.

number &= ~(1 << x);

The XOR operator (^) can be used to toggle a bit.

number ^= 1 << x;

July 11, 2014

To check if a file exists in C you can use the follwing snippet.

#include <unistd.h>  
  
int fileExists(const char *filename) {  
    return !access(filename, F_OK);  
}

July 9, 2014

To generate a random number in C you can use the following snippet.

srand(time(NULL));
int r = rand() % 10; //generates a random number between 0 and 9
printf("%d",r);

July 9, 2014

To get the char code in C you can use the following snippet.

char testChar = 'a';
printf("%d",testChar);