实验3

实验1

#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);

 3.2.1

#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;
return p;
}

 3.2.2

#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;
}

 3.3.1

#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=%11d\n",n,f);
        
    }
    
    return 0;
}

long long func(int n)
{
    long long int f;
    if(n==1)
    f=1;
    else
    f=2*func(n-1)+1;
    return f;
}

 3.4

#include <stdio.h>
int func(int n, int m){
    if(n<m) return -1;
    else if(n==m) return 1;
    else if(m==0) return 1;
    else if(m==1) return n;
    return func(n-1,m)+func(n-1,m-1) ;
     
}
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;
} 

 3.5

#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 s = 1;
     
    if(y == 0)
        return 1;
    else if(y > 0)
    {
        for( ; y > 0; y--)
            s *= x;
    }
    else if(y < 0)
    {
        for( ; y < 0; y++)
            s /= x;
    }
     
    return s;
}

#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)
{
    if(y == 0)
        return 1;
    else if(y > 0)
        return x*mypow(x, y-1);
    else if(y < 0)
        return mypow(x, y+1)/x;
         
}

 3.6

#include<stdio.h>
#include<stdlib.h>
void hanoi(unsigned int n,char from, char temp, char to);
void moveplate(unsigned int nth,char from,char to);
int main(){
    unsigned int n;
    while(scanf("%u",&n) !=EOF)
    hanoi(n,'A','B','C');
    return 0; 
    
} 

void hanoi(unsigned 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 nth,char from,char to){
    
    printf("%u:%c-->%c\n",nth,from,to);
}

 3.7

#include<stdio.h>
int is_prime(int n);
int main()
{
    int n,i;
    for(n=4;n<=20;n+=2)
    {
        for(i=2;i<=(n/2);i++)
        {
            if(is_prime(i)&&is_prime(n-i))
            {
                printf("%d = %d + %d\n",n,i,n-i);
                break;
            }
        }
    }
    return 0;
 } 
 int is_prime(int n)
 {
     int i,flag=1;
     for(i=2;i<n;i++)
     {
         if(n%i==0)
             flag=0;
     }
     return flag;
 }

 3.8

#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;
}