实验三

task1

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <windows.h>
#define N 80

void print_text(int line, int col, char text[]);  // 函数声明 
void print_spaces(int n);  // 函数声明 
void print_blank_lines(int n); // 函数声明 

int main() {
    int line, col, i;
    char text[N] = "hi, April~";
    
    srand(time(0)); // 以当前系统时间作为随机种子
    
    for(i = 1; i <= 10; ++i) {
        line = rand() % 25;
        col =  rand() % 80;
        print_text(line, col, text);
        Sleep(1000);  // 暂停1000ms
    }
    
    return 0; 
}

// 打印n个空格 
void print_spaces(int n) {
    int i;
    
    for(i = 1; i <= n; ++i)
        printf(" ");
}

// 打印n行空白行
void print_blank_lines(int n) {
    int i;
    
    for(i = 1; i <= n; ++i)
        printf("\n");
 } 

// 在第line行第col列打印一段文本 
void print_text(int line, int col, char text[]) {
    print_blank_lines(line-1);      // 打印(line-1)行空行 
    print_spaces(col-1);            // 打印(col-1)列空格
    printf("%s", text);         // 在第line行、col列输出text中字符串
}

task2

1

#include <stdio.h>
long long fac(int n); // 函数声明

int main() {
    int i, n;

    printf("Enter n: ");
    scanf("%d", &n);

    for (i = 1; i <= n; ++i)
        printf("%d! = %lld\n", i, fac(i));

    return 0;
}

// 函数定义
long long fac(int n) {
    static long long p = 1;

    p = p * n;
    printf("p = %d\n",p);

    return p;
}

2

#include <stdio.h>
int func(int, int);        // 函数声明

int main() {
    int k = 4, m = 1, p1, p2;

    p1 = func(k, m);    // 函数调用
    p2 = func(k, m);    // 函数调用
    printf("%d, %d\n", p1, p2);

    return 0;
}

// 函数定义
int func(int a, int b) {
    static int m = 0, i = 2;

    i += m + 1;
    m = i + a + b;

    return m;
}

task3

#include <stdio.h>
int func(int n, int m);

int main() {
    int n, m;

    while(scanf("%d%d", &n, &m) != EOF)
        printf("n = %d, m = %d, ans = %d\n", n, m, func(n, m));
    
    return 0;
}

int func(int n, int m){
    int result;
    if(n==m||m==0)
       result = 1;
    else if(m>n)
       result = 0;
    else   
       result = func(n-1,m-1) + func(n-1,m);
    return result;
}

task4

#include <stdio.h>
int func(int n, int m);

int main() {
    int n, m;

    while(scanf("%d%d", &n, &m) != EOF)
        printf("n = %d, m = %d, ans = %d\n", n, m, func(n, m));
    
    return 0;
}

int func(int n, int m){
    int result;
    if(n==m||m==0)
       result = 1;
    else if(m>n)
       result = 0;
    else   
       result = func(n-1,m-1) + func(n-1,m);
    return result;
}

task5

#include <stdio.h>
double mypow(int x, int y);   // 函数声明 

int main() {
    int x, y;
    double ans;
    
    while(scanf("%d%d", &x, &y) != EOF) {
        ans = mypow(x, y);        // 函数调用
        printf("%d的%d次方: %g\n\n", x, y, ans);
    }
    return 0;
} 

double mypow(int x, int y){
     double ans=1.0;
    int i=1;
    if(y>=0){
        for(;i<=y;i++)
        ans = ans * x;
        }
    else{
        for(;i<=-y;i++)
        ans = ans / x;
    }
    return ans;    
}

#include <stdio.h>
double mypow(int x, int y);   // 函数声明 

int main() {
    int x, y;
    double ans;
    
    while(scanf("%d%d", &x, &y) != EOF) {
        ans = mypow(x, y);        // 函数调用
        printf("%d的%d次方: %g\n\n", x, y, ans);
    }
    return 0;
} 

 
double mypow(int x,int y){
   double ans;
    if(y==0)
    ans = 1;
    else if(y>0){
        if(y==1)
        ans = x;
        else
        ans = x * mypow(x,y-1);}
    else
    ans = 1 / mypow(x,-y);
    
    return ans;
}

task6

#include<stdio.h>
#include<stdlib.h>
void hanoi(unsigned int n,char from,char temp,char to);//递归函数声明 
void moveplate(unsigned int n,char from,char to); //移动函数声明
int time;

int mian(){
    unsigned int n;
    while (scanf("%u",&n) !=EOF){//输入盘子数目
    time = 0; 
    hanoi(n,'A','B','C');
    printf("一共移动了%d次",time);
     }
    system("pause");
    return 0; 
} 

void hanoi(unsigned int n,char from,char temp,char to){
    if(n==1)
       moveplate(n,from,to);
    else
    {
        hanoi(n-1,from,to,temp);//将n-1个盘子从A以C为中心转移到B上 
        moveplate(n,from,to);    //将盘子n从A移到C上 
        hanoi(n-1,temp,from,to);//将n-1个盘子从B以A为中转移到C上    
    }
}

void moveplate(unsigned int n,char from,char to){
    printf("%u:%c-->%c\n",n,from,to);
    time++;    
}

task7

#include<stdio.h>
#include<math.h>
#include<stdlib.h>
int is_prime(int n);

int main(){
    int i,p,q,n,p_flag,q_flag;
    while (scanf("%d",&n)!=EOF){
    
    if((n%2==1)||n<4){
        printf("数据输入错误\n");
        exit(0);
    }
    
    do{
        p=p+1;
        q=n-p;
        p_flag=is_prime(p);
        q_flag=is_prime(q);
    }
    while(p_flag*q_flag==0);
    printf("%d=%d+%d\n",n,p,q);
}
    return 0;        
}

int is_prime(int n){
    int i,m;
    m = sqrt(1.0 * n);
    for(i=2;i<=m;i++)
       if(n%i==0)
       break ;
       
       if(i>m&&n!=1)
       return 1;
       else
       return 0;
}

task8

#include <stdio.h>
#include <math.h>
#include <stdlib.h> 
long func(long s);   // 函数声明

int main() {

    long s, t;

    printf("Enter a number: ");
    while (scanf("%ld", &s) != EOF) {
        t = func(s); // 函数调用
        printf("new number is: %ld\n\n", t);
        printf("Enter a number: ");
    }

    return 0;
}

// 函数定义
long func(long s){
     int i=0,m,result=0,p;
     
     for(;s>1;){
        p = (s%10)%2;
        
        if(p!=0){
        m = s%10;
        result = result + pow(10,i)*m;
        i++;
        } 
        s = s/10;
    }
    return result;
}