C

fwrite c

#include<stdio.h>

int main () {
   FILE *fp;
   char str[] = "This is tutorialspoint.com";

   fp = fopen( "file.txt" , "w" );
   fwrite(str , 1 , sizeof(str) , fp );

   fclose(fp);
  
   return(0);
}

fwrite in c

size_t fwrite(const void *ptr, size_t size, size_t nmemb, FILE *stream)

fwrite c

fwrite (buffer /*ptr*/, 1 /*size [byteweise]*/, sizeof(buffer) /*nmemb*/, dstfile /*stream*/);