PAT甲级C语言.1007. 素数对猜想

#include<stdio.h>#include<math.h>int main(){int i,j,k,temp,n=0;int s=2;scanf("%d",&k);if(k==1) return 0;elsefor(i=2;i<=k;i++){temp=sqrt(i);for(j=2;j<=temp;++j)if(i%j==0) break;if(j>=temp+1){if((i-s)==2)n++;s=i;}}printf("%d",n);return 0;}