Exercise 4-11 Counting Prime Numbers and Summing (20 points)
This question requires counting the number of prime numbers in the interval of a given integer M and N and summing them.
Input format:
Input two positive integers M and N (1≤M≤N≤500) in one line.
Output format:
output the number of prime numbers and their sum in M and N intervals in a row, separated by spaces.
Input sample:
10 31
Output sample:
7 143
#include<stdio.h>
#include<math.h>
int isPrime(int n)
{
int i;
int flag=1;
if(n==1)
flag=0;
else
for(i=2;i<=sqrt(n);i++)
{
if(n%i==0)
flag=0;
}
return flag;
}
int main()
{
int m,n,i;
int num=0,sum=0;
scanf("%d %d",&m,&n);
for(i=m;i<=n;i++)
{
if(isPrime(i))
{
num++;
sum+=i;
}
}
printf("%d %d",num,sum);
}