如何停止从C中的文件读取

#include <stdio.h>

int main(void){
    FILE *fr;            /* declare the file pointer */

    fr = fopen ("some.txt","r");  /* open the file for reading */
        /* elapsed.dta is the name of the file */
        /* "rt" means open the file for reading text */
    char c;
    while((c = getc(fr)) != NULL)
    {
        printf("%c",c);
    }
    fclose(fr);  /* close the file prior to exiTing the routIne */
    /*of main*/ 


    return 0;
}@H_489_3@