2021-11-09

 #include <stdio.h>
 int main(void)
 {
//4.1   
//二
//（2)
/*
int n,s,i;
s=0;
scanf("%d",&n);
for(i=0;n>0;i++){
    s=s+n%10;
    n=n/10;     
} 
printf("%d %d\n",i,s);*/
//(3)
/*
int n,max,min,s,i;
printf("enter n:");
scanf("%d",&n);
printf("enter 4 numbers:");
max=min=scanf("%d",&s);
for(i=1;i<n;i++)
{
    scanf("%d",&s);
    if(max<s)
        max=s;
    else if(min>s)
        min=s;      
} 
printf("max=%d min=%d\n",max,min);  */
//(4)
//(4)
/*
int n,m,i,k,sq,flag,s;
s=k=0;
printf("Enter m,n:");
scanf("%d%d",&m,&n);
for(;m<=n;m++)
{
    flag=1;/////每次假设m为质数 
    sq=sqrt(m);
    for(i=2;i<=sq;i++)
    {
        if(m%i==0)
        {
            flag=0;
            break;
        }           
    }
    if(flag){
            k++;
            s+=m;
    }
}
printf("%d %d",k,s);*/
//4.2(2) 

/*
int n,i,t,s;
printf("Enter n:");
scanf("%d",&n);
for(i=ceil(pow(10,n-1));i<ceil(pow(10,n));i++)
{
    s=0;
    for(t=i;t>=1;t=t/10){
        //q=ceil(11);
        s=s+ceil(pow(t%10,n));
    }
    if(s==i)
        printf("%d\n",i);
}*/ 
//改错题 
/*  
int denominator,flag;
double eps,item,sum;
flag=1;
denominator=1;
sum=0;
printf("Enter eps:");
scanf("%lf",&eps); 
    do{
    item=1.0*flag/denominator;
    sum=sum+item; flag=-flag; denominator=denominator+3;
} while(fabs(item)>eps); printf("sum=%.6f\n",sum);*/



/*
int flag,i,j,m,n,s;
printf("Enter m,n:");
scanf("%d%d",&m,&n);
flag=0; 
for(i=m;i<=n;i++){
    s=0;////////////////
    for(j=1;j<=i/2;j                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                ++){    
        if(i%j==0){///////////
            s=s+j;
        }
    }
    if(i==s){
        flag=1;
        printf("%d=1",i);
        for(j=2;j<=i/2;j++){
            if(i%j==0){printf("+%d",j);}//////////
        }
        printf("\n");

    } 
}
if(flag==0){
    printf("None\n");
}*/

return 0;
}