hi , i have a file which contain 16 elements....now i want to make a different file which will have a nice looking 4 x 4 matrix made of from those 16 elements....i am writing in C . how can i do that??? blue_gene thanks

Read the data into a 2D array. Use a local variable to keep track of how many digits have been read, and then increment your indexes appropriately, and write the stuff out with a couple of loops. myarray[4][4]; or write the numbers as you read them in. count = 0; while(some_in_file) { read in val; if(count == 3) { fprintf(outf, "\n"); count = 0; } fprintf(outf, "%3d ", val); count++; } Something like that. I'm a bit distracted at the moment, so check your data before writing or adding elements, and watch for overflow errors. :P

hi i was writing this way....but getting some errors at runtime(acesses violation in VC++) #include<stdio.h> main() { FILE *fp,*gp; fp=fopen("c:\\x.dat","r"); gp = fopen("c:\\y.dat","w"); int a; printf("hello"); int *buff; buff = NULL; printf("hi"); do { fread(buff,sizeof(int),3,fp); fprintf(gp,"%d\t%d\t%d",buff[0],buff[1],buff[2]); fprintf(gp,"\n"); }while(!feof(fp)) ; fclose(fp); fclose(gp); } why acesses violation??????????

because you haven't allocated any memory for the buff pointer

In other words dont use int *buf; but int buf[5]; or whatever number of elements you would like to have

thanks... i got it