C语言算法（一）基础
代码来自C语言编程百例
一、魔方阵
矩阵阶数是 3
8 1 6
3 5 7
4 9 2
for(i=1; i<=n; i++)
for(j=1; j<=n; j++)
array[i][j] = 0;
/* 建立魔方阵 */
j = n/2 + 1;
array[1][j] = 1;
for(k=2; k<=n*n; k++)
{
i = i - 1;
j = j + 1;
if((i<1) && (j>n))
{
i = i + 2;
j = j - 1;
}
else
{
if(i < 1)
i = n;
if(j > n)
j = 1;
}
if(array[i][j] == 0)
array[i][j] = k;
else
{
i = i + 2;
j = j - 1;
array[i][j] = k;
}
}
i, j均是从1开始计数
链表
#include <stdio.h>
#include <stdlib.h>
struct chain
{
int value;
struct chain *next;
};
struct chain *create()
{
struct chain *head, *tail, *p;
int x;
head = tail = NULL;
printf("Input data.\n");
while (scanf("%d",&x) == 1) /*如果输入的是一个整型的数据，那么向下执行*/
{
p = (struct chain *)malloc (sizeof (struct chain));
/*首先为要新创建的表元p开辟一个内存空间*/
p->value = x;
p->next = NULL;
if(head == NULL)
head = tail = p;
else
/*tail为倒数第二个表元指针，tail->始终指向最后一个表元*/
tail = tail ->next;
tail ->next = p;
}
return head;
}
void main(){
struct chain *p,*q;
q = create();
while(q) {
printf("%d\n",q->value);
p = q->next;
free(q);
q = p;
}
}
#include <stdio.h>
#define Max 100
void SetNull(int *front, int *rear)
{
*front = 0;
*rear = 0;
}
int Empty(int *front, int *rear)
{
if(*front == *rear)
return(1);
else
return(0);
}
int EnQueue(int q[],int x,int *front, int *rear)
{
*rear = (*rear+1) % Max;
if(*front == *rear)
{
printf("队列发生上溢\n");
return(-1);
}
else
{
q[*rear] = x;
return(0);
}
}
int DelQueue(int q[], int *y, int *front, int *rear)
{
*front = (*front +1)%Max;
if(*front == *rear)
{
printf("队列发生下溢\n");
return(-1);
}
else
{
*y = q[*front];
return(0);
}
}
void main()
{
int q[Max];
int f = 0, r = 0; /*f和r分别对应队列的头和尾在整个队列存储区域的位置*/
int i,x,m,n;
int a;
SetNull(&f,&r); /*清空队列*/
printf("要输入队列的字符个数：\n");
scanf("%d",&m);
printf("输入队列的整型数据：\n");
for (i=0; i<m; i++)
{
i=i;
scanf("%d",&x);
a = EnQueue(q,x,&f,&r);
if(a == -1)
break;
}
printf("要提出队列的字符个数：");
scanf("%d",&n);
printf("输出从队列中提取的数据：\n");
for (i = 0; i<n; i++)
{
if(DelQueue(q,&x,&f,&r) == -1)
break;
printf("%d\n",x);
}
if(Empty(&f,&r) == 1)
printf("队列为空");
else
printf("队列中还有%d个数据",(m-n));
}
栈
#include <stdio.h>
#include <stdlib.h>
#define Max 100
int *p;
int *tos;
int *bos;
/*添加一个数据放到堆栈对顶端*/
void push(int i)
{
if(p > bos)
{
printf("堆栈以满\n");
return;
}
*p = i;
p++;
}
/*丛堆栈顶端取出一个数据*/
int pop(void)
{
p--;
if(p < tos)
{
printf("堆栈下溢\n");
return 0;
}
return *p;
}
void main(void)
{
int a,b;
char s[80];
p = (int *)malloc(Max*sizeof(int));
if(!p)
{
printf("分配内存失败");
exit(1);
}
tos = p;
bos = p + Max -1;
printf("请输入第一个数据:\n");
scanf("%d",&a);
push(a);
printf("请输入第二个数据:\n");
scanf("%d",&b);
push(b);
printf("请输入操作符:\n");
scanf("%s",s);
switch (*s)
{
case '+':
a = pop();
b = pop();
printf("结果是a+b = %d\n",(a+b));
push(a+b);
break;
case '-':
a = pop();
b = pop();
printf("结果是a-b = %d\n",(a-b));
push(a-b);
break;
case '*':
a = pop();
b = pop();
printf("结果是a*b = %d\n",(a*b));
push(a*b);
break;
case '/':
a = pop();
b = pop();
printf("结果是a/b = %d\n",(a/b));
push(a/b);
break;
default:
printf("请输入正确操作符\n");
}
}
二叉树
#include <stdio.h>
#include <stdlib.h>
struct tree
{
char info;
struct tree *left;
struct tree *right;
};
struct tree *root; /*树的第一个结点*/
struct tree *construct(struct tree *root, struct tree *r, char info);
void print(struct tree *r, int l);
int main(void)
{
char s[80];
root = NULL;
do
{
printf("请输入一个字符:");
gets(s);
root = construct(root,root,*s);
}while(*s);
print(root,0);
return 0;
}
struct tree *construct(
struct tree *root,
struct tree *r,
char info)
{
if(!r)
{
r = (struct tree *)malloc(sizeof(struct tree));
if(!r)
{
printf("内存分配失败！");
exit(0);
}
r->left = NULL;
r->right = NULL;
r->info = info;
if(!root)
return r;
if(info < root->info)
root->left = r;
else
root->right = r;
return r;
}
if(info < r->info)
construct(r,r->left,info);
else
construct(r,r->right,info);
return root;
}