作业六

#include<stdio.h>
int main()
{
    int sign(int x);
    int x,y;
    scanf("%d",&x);
    y=sign(x);
    printf("sign(%d)=%d
",x,y);
    return 0;    
} 
int sign(int x)
{
    int y;
    if(x>0)
     y=1;
    else if(x==0)
     y=0;
    else
     y=-1;
    return y;
}

#include<stdio.h>
#include<math.h>
int main()
{
    int c,i,m,n,sum;
    int prime(int m);
    scanf("%d%d",&m,&n);
    c=sum=0;
    for(i=m;i<=n;i++)
    if(prime(i)!=0)
    {
        c++;
        sum=sum+i;
    }
    printf("c=%d,sum=%d
",c,sum);
    return 0;
} 
int prime(int m)
{
    int j,i;
    if(m==1)
     return 0;
    j=sqrt(m);
    for(i=2;i<=j;i++)
    if(m%i==0)
     return 0;
    return 1;
#include<stdio.hint main(void)

{
    int c,digit,in;
    int countdigit(int number,int digit);
    scanf("%d%d",&in,&digit);
    c=countdigit(in,digit);
    printf("number %d of digit %d:%d
",in,digit,c);
    return 0;
} 
int countdigit(int number,int digit)
{
    int c;
    if(number<0)
     number=-number;
     c=0;
    do{
        if(number%10==digit)
         c++;
         number=number/10;}while(number!=0);
　　return c;    
}

#include<stdio.h>
int main(void)
{
    int i,m,n;
    int is(int number);
    scanf("%d%d",&m,&n);
    printf("result:
");
    for(i=m;i<=n;i++)
    if(is(i)!=0)
    printf("%d
",i);

    return 0;
}
int is(int number) 
{
    int digit,sum,temp;
    temp=number;
    sum=0;
    while(temp!=0){
        digit=temp%10;
        temp=temp/10;
        sum=sum+digit*digit*digit;
    }
return sum==number;
}

#include<stdio.h>
int even(int n);
int main(void)
{
    int n,sum;
    scanf("%d",&n);
    sum=0;
    while(n>0){
        if(even(n)==0)
         sum=sum+n;
         scanf("%d",&n);
        }
        printf("The sum of the odd numbers is %d.
",sum);
        return 0;
} 
int even(int n)
{
    int y;
    if(n%2==0)
     y=1;
    else 
     y=0;
    return y;
}