96.木桶效应

缓冲区的思维模式==fflush

#include<stdio.h>
#include<stdlib.h>
void main(){
FILE*read = fopen("1.txt","w");
if (!read) {
printf("文件为空");
system("pause");
return;
}
fputs("你好a ", read);
fflush(read);
fputs("你好b ", read);
fputs("你好c ", read);
fclose(read);
system("pause");

}

缓存区的目的就是为了解决性能问题,提高程序运行效率.

---

生成大文件.

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
void main() {



FILE*read = fopen("D:/1/1.txt", "wb");
if (!read) {
printf("文件为空");
system("pause");
return;
}
fseek(read, 6, SEEK_SET);
fputc('', read);
fclose(read);

system("pause");
}
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
void main() {
for (size_t i = 0; i < 5; i++)
{
char out[50] = { 0 };
sprintf(out, "D:/1/%d.txt", i);
FILE*read = fopen(out, "wb");
if (!read) {
printf("文件为空");
system("pause");
continue;
}
fseek(read, 6, SEEK_SET);
fputc('', read);
fclose(read);
}

system("pause");
}

---

通过ftell函数,获取文件大小.

#include<stdlib.h>
#include<stdio.h>
#include<string.h>
void main() {

FILE*read = fopen("D:/1/1.txt", "rb");
if (!read) {
printf("文件为空");
system("pause");
return;
}
fseek(read, 0, SEEK_END);
int count = ftell(read);
fclose(read);
printf("文件大小为:%d ", count);

system("pause");
}