比较三个数大小

int a,b,c；

方法一

int max,median,min;        if(a>b){            if(b>c){                max=a;                median=b;                min=c;            } else {                min=b;                if(a>c){                    max=a;                    median=c;                } else {                    max=c;                    median=a;                }            }        } else {            if(b<c){                max=c;                median=b;                min=a;            } else {                max=b;                if(a>c){                    median=a;                    min=c;                }else{                    median=c;                    min=a;                }            }        }

方法二：从小到大

int t= -1;  // 只使用一个中间变量        if(a>b){            t=a;            a=b;            b=t;        }        if(a>c){            t=a;            a=c;            c=t;        }        if(b>c){            t=b;            b=c;            c=t;        }

方法三
自行写排序算法：冒泡/插入/选择/快速排序…….

方法四
使用类库，Arrays.sort()，内部根据数据项长度自动选择不同方式，具体实现为：

 private static void sort1(int x[], int off, int len) {    // Insertion sort on smallest arrays    if (len < 7) {        for (int i=off; i<len+off; i++)        for (int j=i; j>off && x[j-1]>x[j]; j--)            swap(x, j, j-1);        return;    }    // Choose a partition element, v    int m = off + (len >> 1);       // Small arrays, middle element    if (len > 7) {        int l = off;        int n = off + len - 1;        if (len > 40) {        // Big arrays, pseudomedian of 9        int s = len/8;        l = med3(x, l,     l+s, l+2*s);        m = med3(x, m-s,   m,   m+s);        n = med3(x, n-2*s, n-s, n);        }        m = med3(x, l, m, n); // Mid-size, med of 3    }    int v = x[m];    // Establish Invariant: v* (<v)* (>v)* v*    int a = off, b = a, c = off + len - 1, d = c;    while(true) {        while (b <= c && x[b] <= v) {        if (x[b] == v)            swap(x, a++, b);        b++;        }        while (c >= b && x[c] >= v) {        if (x[c] == v)            swap(x, c, d--);        c--;        }        if (b > c)        break;        swap(x, b++, c--);    }    // Swap partition elements back to middle    int s, n = off + len;    s = Math.min(a-off, b-a  );  vecswap(x, off, b-s, s);    s = Math.min(d-c,   n-d-1);  vecswap(x, b,   n-s, s);    // Recursively sort non-partition-elements    if ((s = b-a) > 1)        sort1(x, off, s);    if ((s = d-c) > 1)        sort1(x, n-s, s);    }