实验3

实验任务1

源代码

#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);
}

功能：分别在0~24行，0~79列中随机选一行一列，在第line行打印（line-1）行空行，第col列打印（col-1）列空格，在第line行第col列输出“hi, April~”，重复运行10次，每次间隔1000ms

 

实验任务2

task2_1.c源代码

#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;
}

增加一行源代码后运行截图

 

task2_2.c源代码

#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;
}

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static变量特性：对变量只赋初值一次，再次调用函数时保留上次函数运行结束时的值

 

实验任务3

源代码

#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){
 long long f;
 if(n==0)
     f=0;
 else
     f=(func(n-1)+1)*2-1;
 return f;
}

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实验任务4

源代码

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

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实验任务5

task5_1源代码

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

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task5_2源代码

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

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实验任务6

源代码

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

int main(){
    unsigned int n;
    int a=0;
    while(scanf("%u",&n)!=EOF){
        hanoi(n,'A','B','C');
        printf("\n");
        a=pow(2,n)-1;
        printf("一共移动了%d次\n\n",a);
    }
    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);
}

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实验任务7

源代码

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

int main(){
    int j,k;
    while(scanf("%d",&j)!=EOF){
        for(k=1;k<=j;k++)
            if(is_prime(k)&&is_prime(j-k))break;
        printf("%d=%d+%d\n",j,k,j-k);
    }
    return 0;
}

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

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实验任务8

源代码

#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("nem 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;
}

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