primesInAFile.c

#include <stdio.h>

int ehprimo(int);

int main(void){

    FILE *fp;
    fp = fopen("testefileC.txt", "w");

    int i = 0;
    int qnt = 200000;
    int num = 2;

    while(i != qnt){
        if(ehprimo(num)){
            fprintf(fp, "%d\n", num);
            i++;
        }
        num++;
    }
    fclose(fp);
}

int ehprimo(int x){
    int i;
    for(i = 2; i < x/2+1; i++){
        if((x % i) == 0){
            return 0;
        }
    }
    return 1;
}