Conjecture of prime pairs in C language

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Algorithm design ideas

1. Get prime （ Be careful , This part of the course has run timeout , Use sqrt Can solve ）
2. Judge whether prime numbers are adjacent
3. Print the results

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Code

#include <stdio.h>
#include <math.h>

int issushu(int x){
    
    int count = 0;
    for(int i=2; i<sqrt(x)+1; i++){
    
        if(x % i==0){
    
            return 0;
        }
    }
    return 1;
}

int main(){
    
    int n, i;
    int x=0;
    scanf("%d", &n);
    for(i=5; i<=n; i++){
    
        if(issushu(i-2) && issushu(i)){
    
            x++;
        }
    }
    printf("%d", x);
    return 0;
}

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Running results