[C/C++]洗牌算法

#include
#include
#include
int  d[6];
int  i,n,a,b,t;
int  c,j;
void  main() {
    srand ( time (NULL));
    printf ( "shuffle 0..n-1 demo\n" );
    for  (n=1;n<=5;n++) { /* 测试1～5个元素 */
        printf ( "_____n=%d_____\n" ,n);
        j=1;
        for  (c=1;c<=n;c++) j=j*c; /* j为n! */
        j*=n*2;
        for  (c=1;c<=j;c++) { /* 测试n*2*n!次 */
            for  (i=0;i /* 填写0～n-1 */

            for  (i=n;i>0;i--) { /* 打乱0～n-1 */
                a=i-1;b= rand ()%i;
                if  (a!=b) {t=d[a];d[a]=d[b];d[b]=t;}
            }
            printf ( "%04d:" ,c);
            for  (i=0;i printf ( "%d" ,d[i]);

            printf ( "\n" );
        }
    }
    printf ( "shuffle 1..n demo\n" );
    for  (n=1;n<=5;n++) { /* 测试1～5个元素 */
        printf ( "_____n=%d_____\n" ,n);
        j=1;
        for  (c=1;c<=n;c++) j=j*c; /* j为n! */
        j*=n*2;
        for  (c=1;c<=j;c++) { /* 测试n*2*n!次 */
            for  (i=1;i<=n;i++) d[i]=i; /* 填写1～n */
            for  (i=n;i>1;i--) { /* 打乱1～n */
                a=i;b= rand ()%i+1;
                if  (a!=b) {t=d[a];d[a]=d[b];d[b]=t;}
            }
            printf ( "%04d:" ,c);
            for  (i=1;i<=n;i++)  printf ( "%d" ,d[i]);
            printf ( "\n" );
        }
    }
}