Novice, please attention, share c language homework every day, thank you for attention, collection!!!!!! If you are also learning c, come on, every day to share high quality questions and answers!

CodePudding user response:

 title description: 

A prime number, which in turn from low remove one, two,... , if the income of each number is prime, still called super primes, 

For example: 7331 was a four super prime because 7,73,733,7331 are prime. Try to within 1000 ~ n (1000 & lt; n
 CodePudding user response: 
 
Bool IsPrime (int n) 
{
If (n==1) 
return false; 

If (n==2 
| | n==3 
| | n==5 
| | n==7) 
{
return true; 
} 

If (n % 2==0) 
return false; 

If (n % 3==0) 
return false; 

If (n % 5==0) 
return false; 

If (n % 7==0) 
return false; 

Double dn=SQRT (n); 
Int CNT=(int) dn. 
For (int I=2; i <=CNT; + + I) 
{
If I (n %==0) 
return false; 
} 

return true; 
} 

Void Test (void) 
{
Int n=0; 
Printf (" please enter n (1000 & lt; n<9999) : "); 
Scanf_s (" % d ", & amp; n); 
If (n & lt;=1000 | | 9999 & lt;=n) 
{
Printf (" input error!" ); 
return; 
} 

int count=0; 
int sum=0; 
Int Max=0; 
For (int I=2001; i <=n; + + I) 
{
Int test=I; 
If (IsPrime (test)) 
{
The test/=10; 
If (IsPrime (test)) 
{
The test/=10; 
If (IsPrime (test)) 
{
The test/=10; 
If (IsPrime (test)) 
{
+ + count; 
The sum +=I; 
Max=I; 
Printf (" % d \ r \ n ", I); 
} 
} 
} 
} 
} 

Printf (" (1) the number of super prime: % d \ r \ n (2) the sum of all the primes: % d \ r \ n (3) the largest super prime: % d \ r \ n ", count, sum, Max). 
} 
 

Please enter n (1000 & lt; n<9999) : 8000 
2333 
2339 
2393 
2399 
2939 
3119 
3137 
3733 
3739 
3793 
3797 
5939 
7193 
7331 
7333 
7393 
(1) the number of super prime: 16 
(2) the sum of all the primes: 68910 
(3) the largest super prime number: 7393 
Please press any key to continue...
 CodePudding user response: 
The 
 
 reference 1/f, confident boy reply: 
 
 
 title description: 

A prime number, which in turn from low remove one, two,... , if the income of each number is prime, still called super primes, 

For example: 7331 was a four super prime because 7,73,733,7331 are prime. Try to within 1000 ~ n (1000 & lt; n<9999) : (1) the number of super prime (2) the sum of all the primes (3) the largest super primes, 
 
 
 

 
Bool IsPrime (int n) 
{
If (n==1) 
return false; 

If (n==2 
| | n==3 
| | n==5 
| | n==7) 
{
return true; 
} 

If (n % 2==0) 
return false; 

If (n % 3==0) 
return false; 

If (n % 5==0) 
return false; 

If (n % 7==0) 
return false; 

Double dn=SQRT (n); 
Int CNT=(int) dn. 
For (int I=11; i <=CNT; + + I)//optimization, starting from 11 
{
If I (n %==0) 
return false; 
} 

return true; 
} 

Void Test (void) 
{
Int n=0; 
Printf (" please enter n (1000 & lt; n<9999) : "); 
Scanf_s (" % d ", & amp; n); 
If (n & lt;=1000 | | 9999 & lt;=n) 
{
Printf (" input error!" ); 
return; 
} 

int count=0; 
int sum=0; 
Int Max=0; 
For (int I=2001; i <=n; + + I) 
{
Int test=I; 
If (IsPrime (test)) 
{
The test/=10; 
If (IsPrime (test)) 
{
The test/=10; 
If (IsPrime (test)) 
{
The test/=10; 
If (IsPrime (test)) 
{
+ + count; 
The sum +=I; 
Max=I; 
Printf (" % d \ r \ n ", I); 
} 
} 
} 
} 
} 

Printf (" (1) the number of super prime: % d \ r \ n (2) the sum of all the primes: % d \ r \ n (3) the largest super prime: % d \ r \ n ", count, sum, Max). 
} 
 CodePudding user response: 
 
Bool IsPrime (int n) 
{
If (n==1) 
return false; 

If (n==2 
| | n==3 
| | n==5 
| | n==7) 
{
return true; 
} 

If (n % 2==0) 
return false; 

If (n % 3==0) 
return false; 

If (n % 5==0) 
return false; 

If (n % 7==0) 
return false; 

Double dn=SQRT (n); 
Int CNT=(int) dn. 
For (int I=11; i <=CNT; I +=2)//continue to optimize the I +=2 
{
If I (n %==0) 
return false; 
} 

return true; 
}