24
File
#include <stdio.h>
int main(void) {
    FILE* fp;
    int a;
    scanf("%d",&a);
    fp=fopen("test.txt","w");
    if(fp==NULL) {
        puts("File open error!");
        return 1;
    }
    fprintf(fp,"%d\n",a);
    fclose(fp);
    a=0;
    printf("a=%d\n",a);
    fp=fopen("test.txt","r");
    if(fp==NULL) {
        puts("File open error!");
        return 1;
    }
    fscanf(fp,"%d",&a);
    fclose(fp);
    printf("a=%d\n",a);
    return 0;
}