Edit Question - KnowledgeHub

Title Body

So(just for fun), i was just trying to write a C code to copy a file. I read around and it seems that all the functions to read from a stream call fgetc() (I hope this is this true?), so I used that function: #include <stdio.h> #include <stdlib.h> #include <time.h> #define FILEr "img1.png" #define FILEw "img2.png" main() { clock_t start,diff; int msec; FILE *fr,*fw; fr=fopen(FILEr,"r"); fw=fopen(FILEw,"w"); start=clock(); while((!feof(fr))) fputc(fgetc(fr),fw); diff=clock()-start; msec=diff*1000/CLOCKS_PER_SEC; printf("Time taken %d seconds %d milliseconds\n", msec/1000, msec%1000); fclose(fr); fclose(fw); } This gave a run time of 140 ms for this file on a 2.10Ghz core2Duo T6500 Dell inspiron laptop. However, when I try using fread / fwrite , I get decreasing run time as I keep increasing the number of bytes(ie. variable st in the following code) transferred for each call until it peaks at around 10ms! Here is the code: #include <stdio.h> #include <stdlib.h> #include <time.h> #define FILEr "img1.png" #define FILEw "img2.png" main() { clock_t start,diff; // number of bytes copied at each step size_t st=10000; int msec; FILE *fr,*fw; // placeholder for value that is read char *x; x=malloc(st); fr=fopen(FILEr,"r"); fw=fopen(FILEw,"w"); start=clock(); while(!feof(fr)) { fread(x,1,st,fr); fwrite(x,1,st,fw); } diff=clock()-start; msec=diff*1000/CLOCKS_PER_SEC; printf("Time taken %d seconds %d milliseconds\n", msec/1000, msec%1000); fclose(fr); fclose(fw); free(x); } Why this is happening? I.e if fread i

Tags (comma-separated) Cancel