Random_n in C Language

 

Some data is always input manually during algorithm sorting, which is somewhat inconvenient and acceptable for small data input. However, when the data volume reaches K level, it becomes complex. We also need to ensure that the input data is not too many duplicates or does not repeat, which is a test of our memory. All I write a program that generates N unordered integers. This program can generate N numbers, which are different from 0 to N.

 

The Code is as follows:

 

# Include <stdio. h>

# Include <stdlib. h>

# Include <time. h>

 

# Define MAX_NUM 10 // data volume to be generated

 

Void random_n (int a [], int n); declare the random_n Function

 

Int main ()

{

Int a [MAX_NUM], I = 0, j = 0;

While (j <MAX_NUM)

{

A [j] =-1; // initialization, which is very important. a large heel header was previously planted during initialization.

J ++;

}

Random_n (a, MAX_NUM );

While (I <MAX_NUM)

{

Printf ("% d \ t", a [I]);

I ++;

}

Printf ("\ n ");

Return 0;

}

Void random_n (int a [], int n)

{

Int temp = 0, j = 0, count = 0, I = 0;

Srand (time (0 ));

While (count <n)

{

Printf ("\ nStart! \ N ");

Temp = rand () % n;

Printf ("\ ncount = % d, temp = % d", count, temp );

For (j = 0; j <count; j ++)

{

If (a [j] = temp)

{

Printf ("Find! \ N ");

I = 1;

Break;

}

Else

{

I = 0; // mark

}

}

If (j = count & I = 0) // The comparison is complete and the same

{

Printf ("\ nNOT Find! \ N ");

A [count] = temp;

Count ++;

}

}

 

}

Running result: zookeeper

 

After adding this small function, we can directly call this function when entering algorithm data. First, declare an array containing MAX_NUM elements, and then pass the parameter to the random_n function. The worst running condition of the algorithm is O (N ^ 2), and the best running condition is O (N ).

 

 

This algorithm is not very efficient. I will introduce you to a more efficient method for generating unordered numbers.

From Mingyue Tianya