譬如,4,7,16=4x4,28=4x7,44,47,49=7x7,64=4x4x4;74,77等等.
我用vc08编译之后总是不对,显示不如16等等.
code:
#include<stdio.h>
int bonheur(int n){
       while(n!=0){
              if(n%10==4||n%10==7){
                     n=n/10;
                    }
                else  {
                       return 0;
}
}
         
          while(n>1){
                 if (n/4==0) n=n/4;
                 else  {
                      if(n/7==0) n=n/7;
                      else {
                         return 0;
                }
}
}
return 1;
}

int main(){
int n,m;
printf("donner n est:\n");
scanf("%d",&n);
printf("donner m est:\n");
scanf("%d",&m);
int i;
for(i=n;i<m;i++){
    if(bonheur(i)==1){
       printf("%d\n",i);
   }
}
return 0;
}

试了,不行.

是阿,两个函数简单,但题目要求只能用一个函数

大体搞定了
#include<stdio.h>

int bonheur(int n){
    int n1=n;
       while(n1!=0){
              if(n1%10==4||n1%10==7){
                     n1=n1/10;
                    }
                else  {
                    break;}
       }
       if(n1==4||n1==7) return 1;
       else
           
         if(n==1) return 0;
        while(n>1){
                 if (n%4==0) n=n/4;
                 else  {
                      if(n%7==0) n=n/7;
                      else {
                          return 0;}
                 }
        }

return 1;
}

int main(){
int n,m;
printf("donner n est:\n");
scanf("%d",&n);
printf("donner m est:\n");
scanf("%d",&m);

int i;
for(i=n;i<m;i++){
    if(bonheur(i)==1){
       printf("%d\n",i);
   }

}
return 0;
}

还有一个问题就是这个while函数,为什么用>1的时候就可以,>0的时候就不可以呢?
比如这样就不行
  while(n>0){
                 if (n%4==0) n=n/4;
                 else  {
                      if(n%7==0) n=n/7;
                      else {
                          return 0;}
                 }
        }

return 1;
这样就可以了
  if(n==1) return 0;
        while(n>1){
                 if (n%4==0) n=n/4;
                 else  {
                      if(n%7==0) n=n/7;
                      else {
                          return 0;}
                 }
        }

return 1;
}

1 mod 4 = 1 不对吗?