c语言之fprintf函数和ftell的使用

fprintf函数作用:将输出写入到给定的输出流中.
ftell函数作用:ftell() 函数是 C 语言标准库 <stdio.h> 中的一个函数,其作用是获取由 stream 所指向的文件流的文件位置指示器的当前值.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>int main()
{//  int fprintf(FILE *stream, const char *format, ...);//write output to the given output  streamchar name[64] = {0}; char hexnumber[10] = {0x01,0x02,0x03};FILE *file;strcat(name, "rgba555");file = fopen(name, "w");  // 若存在必回擦掉原有内容从头写if (file == NULL) {printf("open %s failed\n", name);//goto ERROR;}//fprintf(file,"Hello %s\n", name);fprintf(file, "0x%02x ,0x%02x ,", hexnumber[0]&0xff, hexnumber[1]&0xff);fprintf(file, "};\n");fclose(file);
}

#include <stdio.h>
#include <stdlib.h>
#include <string.h>int main()
{FILE*fp;int len;fp = fopen("file.txt","r");if( fp == NULL ) {perror ("打开文件错误");return(-1);}fseek(fp,0,SEEK_END);// The ftell() function obtains the current value of the file position indicator for the stream pointed to by streamlen = ftell(fp);fclose(fp);printf("file.txt的总大小=%d字节\n",len);return 0;
}