【C和C++】一些课后习题的解法

---

P219 输入年月日计算是该年的第几天

#include<stdio.h>
int main()
{
int year,month,day;
scanf("%d%d%d",&year,&month,&day);
int runian(int month,int day);
int frunian(int month,int day);
if((year%4==0)&&(year%100!=0)) printf("%d
",runian(month,day));
else if((year%100==0)&&(year%400==0)) printf("%d
",runian(month,day));
else
printf("%d
",runian(month,day)+1);
return 0;
}

int runian(int month,int day)
{
int a[12]={31,28,31,30,31,30,31,30,30,31,30,31};
for(int i=0,sum=0;i<(month-1);i++)
{sum+=a[i];}
return sum+day;
}

---

P291 约瑟夫环 逢3退出

#include <stdio.h>
#include<stdlib.h>
int main()
{
    int n, i, k, m;
    int array[50], *p;
    printf("n = 
");
    scanf("%d", &n);
    p = array;
    for (i = 0; i < n; i++)
        *(p+i) = i+1;
    i = 0;      // i 为每次循环计数变量
    k = 0;     // k 为按1,2,3报数时的计数变量
    m = 0;    // m为退出人数计数变量
    while(m < n-1)      //当退出人数比n-1少时执行循环体
    {
        if( *(p+i) != 0 )
            k++;
        if(k == 3)             // 对退出的人编号置为0
        {
            *(p+i) = 0;
            k = 0;
            m++;
        }
        i++;
        if(i == n)
        i = 0;
    }
    while(*p == 0)
        p++;
    printf("No. %d
", *p);
    return 0;
}

---

 Vedic Square and Vedic Star

#include<iostream>
using namespace std;

int main() {
 int j;  int i;
 int k;
 int a[100][100]={0};
 for (i = 1; i<10; i++)
   a[i][0]=i;
 for (j = 1; j<10; j++)
   a[0][j]=j ;
 for (i = 1; i < 10;i++) {
   for (j = 1; j < 10;j++)    {
    a[i][j] = a[i][0]*a[0][j];
    k= a[i][j];
     if (a[i][j]>9)
      a[i][j] = k / 10 + k % 10;
     if (a[i][j] > 9){
      k = a[i][j];
      a[i][j] = k / 10 + k % 10;
     }
   }
  }
  for (i = 0; i<10; i ++)   {
   for (j = 0; j < 10; j++)
    if (j ==9)
                    cout << a[i][j] << endl;
    else     
cout << a[i][j] ;
  }
  int h;
  cin>>h;
  for (i = 1; i<10; i ++)   {
   for (j = 1; j < 10; j++)
    if (h==a[i][j])
                    cout << '*' ;
    else
    cout <<' ' ;
            cout<<'
';
  }
  return 0;
}

---

elevator

# include <iostream>
using namespace std;

int main(){
int a[100]={0};
int n;
int i;
int sum=0;
cin>>n;
sum=n*5;
for (i=1;i<=n;i++){
cin>>a[i];
}
for (i=1;i<=n;i++){
if(a[i]>a[i-1])
sum+=6*(a[i]-a[i-1]);
else
sum+=4*(a[i-1]-a[i]);
}
cout<<sum<<endl;
return 0;
}

---

约瑟夫环

指针

void Joseph(Node*head,int n,int m)
{    int i,int j;
    Node*p,*q;
    q=head;p=q->next;
    for(j=1)
        {
        for(i=1;i<n;i++){
            q=p;p=p->next;
        }
        printf("%d",p->number);
        q->next=p->next;
        p=q->next;
        free(q->next);
        }
}

数组

void Jopseph(int n,int m)
{    int jopseph[];
    int i=0;int j=n;//i用来计数，j用来改变数组的允许访问长度
    for(int a=0;a++;a<=n)
    {
        joseph[a]=a+1;
    }
    for(int a=0;a++;a<j)
    {    
        i+=1;
        if(a+1>j)
        {
            a=0;
        }
        if(i==m)
        {
            printf("%d",joseph[a]);
            for(int b=a;b++;b<j)
            {
                joseph[b]=joseph[b+1];
                j-=1;

            }
        }
    }  
}