C language implementation with asterisks printed on the screen Diamond __c language

A lot of people first feel must be: very simple ah, not just write a few printf statements

Like this:

#define _crt_secure_no_warnings 1

#include <stdio.h>

int main ()
{
    printf ("   *\n");
    printf ("  ***\n");
    printf ("*****\n");
    printf ("*******\n");
    printf ("*****\n");
    printf ("  ***\n");
    printf ("   *\n");
    System ("pause");
    return 0;
}

It seems to be complete, but if I let you print this diamond is very large, there are many rows, many columns (20 rows, 20 columns), you need a lot of asterisks to do, you have to write this. It's too much trouble.

In fact, as long as found the law ——-when should be printed space, when should print an asterisk, packaged into a function, you can write a write only once, no matter how many rows and columns can be used to use the program, the following is a program such as:

#define _crt_secure_no_warnings 1     

#include <stdio.h>        

void pr_start (int _num)
{
    int n=0;
    int i = 0;
    for (n = 1; n <= 2*_num; n++)         
    {
        int temp = n;
        if (n > _num)
        {
            Temp-= 2 * (n-_num);
        }
        for (i = 1; i < 2 * _num; i++)
        {
            if (i>= (_num-temp + 1)) && (i<= (temp + _num-1))  //Find Value
            {
                printf ("*") is required to output * time I;
            }
            else
            {
                printf ("");
            }
        }
        printf ("\ n")
    ;
}

int main ()
{
    int num = 0;
    printf ("Please enter a number:");
    scanf ("%d", &num);
    Pr_start (num);
    System ("pause");
    return 0;
}

7 Rows, 7 columns:

59 rows, 59 columns:

Program only write once, want to output a n row n column of diamond, only need to enter a (n+1)/2 of the number can be.
The key to the program is to determine when the output ' * ', when the output ' (space).

    for (n = 1; n <= 2*_num; n++)         
    {
        int temp = n;
        if (n > _num)
        {
            Temp-= 2 * (n-_num);
        }
        for (i = 1; i < 2 * _num; i++)
        {
            if (i>= (_num-temp + 1)) && (i<= (temp + _num-1))  //Find needed Output * Time I's value
            {
                printf ("*");
            }
            else
            {
                printf ("");
            }
        }
    }

The above code is the essence of this program to achieve the function, input ' * ' and input ' of the law is also in this area. Here do not give a summary, please draw their own conclusions.
Of course, more than one law, you can think more, to think about what methods can be achieved.