实验三

tsak1

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#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);
}

程序实现功能为每隔1s在第line行第col列打印文本“hi,April~”，共生成十段文本（由主函数中循环控制），每段文本输出由print_text函数实现，其中line和col由随机数生成，print_spaces函数和print_blank_lines函数起定位作用，分别负责打印n个空格和n行空白行。

task2-1:

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#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;
}

tsak2-2

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#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;
}

理论上分析结果为8与17，与实验运行结果相一致，局部static变量的特点是它位于静态存贮区，在函数调用结束后，它的值仍然存在，并可以影响到下一次调用的过程。

tsak3

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#include <stdio.h>
#include<stdlib.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);
    }
    system("pasue");
    return 0;
}

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

task4-1

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#include <stdio.h>
#include<stdlib.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));
    system("pause");
    return 0;
}

int func(int n,int m)
{
    int i,s=1,k=1;
    if(m>n)
    {
        return 0;
    }
    else if(m==0||n==0)
    {
        return 1;
    }
    else
    {
        for(i=1;i<=m;i++)
		    {
                s*=n-i+1;
                k*=i;
            }
		return s/k;
    }

task4-2

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

tsak5

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#include<stdio.h>
#include<stdlib.h>

void hanoi(int n,char from,char temp,char to);
void moveplate(int n,char from,char to);
int sum(int n);
int main()
{
	int n,k;
	char A,B,C;
	while(scanf("%d",&n)!=EOF)
	{
		hanoi(n,'A','B','C');
		k=sum(n);
		printf("一共移动了%d次\n",k);
		system("pause");
	}
	return 0;
}

void moveplate(int n,char from,char to)
{
	printf("%d: %c--> %c\n",n,from,to);
}
void hanoi(int n,char from,char temp,char to)
{
	if(n==1){
		moveplate(n,from,to);
	}
	if(n>1){
		hanoi(n-1,from,to,temp);
		moveplate(n,from,to);
		hanoi(n-1,temp,from,to);
	}
	    
}
int sum(int n){
	if(n==1){
		return 1;
	}
	if(n>1){
		return 2*sum(n-1)+1;
	}
}

task6

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#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 ans;
	long digit,t=1;
	ans=0;
	while(s!=0){
		digit=s%10;
		if(digit%2){
			ans+=t*digit;
			t*=10;
		}
		s/=10;
	}
	return ans;
}