实验3

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[]);
void print_spaces(int n);  
void print_blank_lines(int n); 

int main() {
    int line, col, i;
    char text[N] = "hi, April~";
    
    srand(time(0)); 
    
    for(i = 1; i <= 10; ++i) {
        line = rand() % 25;
        col =  rand() % 80;
        print_text(line, col, text);
        Sleep(1000); 
    }
    
    return 0; 
}

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

void print_blank_lines(int n) {
    int i;
    
    for(i = 1; i <= n; ++i)
        printf("\n");
 } 
 
void print_text(int line, int col, char text[]) {
    print_blank_lines(line-1);      
    print_spaces(col-1);            
    printf("%s", text);        
}

 随机隔n个空白格和空白行打印"hi, April~"

task2.1

#include <stdio.h>
long long fac(int n);

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;
} 

long long fac(int n){
    static long long p = 1;
    
    p = p * n;
    
    return p;
}

#include <stdio.h>
long long fac(int n);

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;
} 

long long fac(int n){
    static long long p = 1;
    
    p = p * n;
    printf("p = %lld\n", p); 
    return p;
}

task2.2

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

int main(){
    int k = 4, m = 1, p1, p2;
    
    p1 = func(k, m);
    p2 = func(k, m);
    printf("%d, %d\n", p1, p2);
        
    return 0;
} 

int func(int a, int b){
    static int m = 0, i = 2;
    
    i += m + 1;
    m = i + a + b;
    
    return m; 
}

 再次调用该函数，将保存上次的结果。

 task3

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

int main() {
    int n;
    long long f;

    while (scanf("%d", &n) != EOF) {
        f = func(n); 
        printf("n = %d, f = %lld\n", n, f);
    }

    return 0;
}

long long func(int n){

   if(n == 1)
     return 1;
   else
     return 2 * func(n - 1) + 1;
}
 

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){
    if(m == 0 || m == n)
      return 1;
    if(m == 1)
      return n;
    if(n < m)
      return 0;
    if(m >1 && n > m)
      return func(n-1, m) + func(n-1, m-1);
}

task5.1

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

int main() {
    int x, y;
    double ans;

    while (scanf("%d%d", &x, &y) != EOF) {
        ans = mypow(x, y); 
        printf("%d的%d次方：%g\n\n", x, y, ans);
    }

    return 0;
}

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

task5.2

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

int main() {
    int x, y;
    double ans;

    while (scanf("%d%d", &x, &y) != EOF) {
        ans = mypow(x, y); 
        printf("%d的%d次方：%g\n\n", x, y, ans);
    }

    return 0;
}

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

}

task6

#include <stdio.h>
#include <stdlib.h>
void hanoi(unsigned int n, char from, char temp, char to);
void moveplate(unsigned int n, char from, char to);
int count;

int main (){
    unsigned int n;
    while(scanf("%u", &n) != EOF){
    count = 0;
    hanoi(n, 'A', 'B', 'C');
    printf("一共移动了%d次\n", count);
    }
    
    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);
        moveplate(n, from, to);
        hanoi(n-1, temp, from, to);
    }
}

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

task7

#include <stdio.h> 
#include <math.h>
int is_prime(int n);
int main()
{
    int i, k, a[15], j = 0, l;
    for (k = 2; k <= 20; k++)
    {
        if (is_prime(k))
            a[j++] = k;
    }
    for (i = 2; i <= 10; i++)
    {
        for (l = 1; l <= 10; l++)
        {

            if (is_prime(2 * i - a[l - 1]))
            {
                printf("%d = %d + %d\n", (2 * i), a[l - 1], (2 * i - a[l - 1])); break;
            }

        }
    }
    return 0;
}
int is_prime(int n)
{
    int i, flag = 1;
    for (i = 2; i <= sqrt(n); i++)
    {
        if (n % i == 0) { flag = 0; break; }
    }
    return flag;
}

task8

#include <stdio.h>
#include <math.h>
long func(long s);

int main(){
    long s, t;
    
    printf("Enter a number: ");
    while(scanf("%ld", &s) != EOF){
        t = func(s);
        printf("new number is: %ld\n\n", t);
        printf("Enter a number: ");
    }
    return 0;
}

long func(long s){
    long b=0,t=0;
    int a,m;
    while(s!=0){
        a=s%10;
        if(a%2!=0)
            b=10*b+a;
        s=s/10;
    }
    
    while(b!=0){
        m=b%10;
        t=10*t+m;
        b=b/10;
    }
    
    return t;
}