generate a random number between 1 and 10 in c

Question

include  lt stdio h gt   include  lt stdlib h gt   int main          int randomnumber      randomnumber   rand     10      printf   d n   randomnumber       return 0      This is a simple program where randomnumber is an uninitialized int variable that is meant to be printed as a random number between 1 and 10  However  it always prints the same number whenever I run over and over again  Can somebody please help and tell me why this is happening  Thank you

User · Answer

Generating a single random number in a program is problematic. Random number generators are only "random" in the sense that repeated invocations produce numbers from a given probability distribution.

Seeding the RNG won't help, especially if you just seed it from a low-resolution timer. You'll just get numbers that are a hash function of the time, and if you call the program often, they may not change often. You might improve a little bit by using srand(time(NULL) + getpid()) (_getpid() on Windows), but that still won't be random.

The ONLY way to get numbers that are random across multiple invocations of a program is to get them from outside the program. That means using a system service such as /dev/random (Linux) or CryptGenRandom() (Windows), or from a service like random.org.

User · Answer

srand time NULL     int nRandonNumber   rand     nMax 1 -nMin    nMin  printf   d n  nRandonNumber

User · Answer

Here is a ready to run source code for random number generator using c taken from this site  http   www random-number com random-number-c    The implementation here is more general  a function that gets 3 parameters  min max and number of random numbers to generate    include  lt time h gt   include  lt stdlib h gt   include  lt stdio h gt      the random function void RandomNumberGenerator const int nMin  const int nMax  const int  nNumOfNumsToGenerate      int nRandonNumber   0    for  int i   0  i  lt  nNumOfNumsToGenerate  i            nRandonNumber   rand    nMax-nMin    nMin      printf   d    nRandonNumber         printf   n       void main       srand time NULL      RandomNumberGenerator 1 70 5

User · Answer

You need a different seed at every execution   You can start to call at the beginning of your program   srand time NULL      Note that   10 yields a result from 0 to 9 and not from 1 to 10  just add 1 to your   expression to get 1 to  10

User · Answer

You need to seed the random number generator  from man 3 rand      If no seed value is provided  the rand   function is automatically seeded with  a value of 1    and     The srand   function sets its argument as the seed for a new sequence of  pseudo-random  integers  to  be  returned  by rand    These sequences are repeatable by calling srand   with the same seed value    e g   srand time NULL

[c] generate a random number between 1 and 10 in c

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