hello everybody. i am working with C.. and i have what i consider a strange problem. if i write the program using printf and scanf it runs, but if i change to using files (fprintf and fscanf) i have problems with dynamic memmory usage. i have managed to isolate the problem to this portion of code. it fails at the line with the "breaks here". i really need help here cause i don't understand why it works when i do not use pointers and doesn't work when i also use files. FILE *fin = fopen ("test.in", "r"); FILE *fout = fopen ("test.out", "w"); char **vp, *buffer=(char *) malloc(15);; int i,n,vi[10],temp,k,j,p; fscanf(fin,"%d", &n); for(i=0; i<n; i++) { fscanf(fin,"%s", buffer); /*breaks here*/ vp=(char *) malloc((strlen(buffer)+1)*sizeof(char)); strcpy(vp,buffer); vi=0; }

From the shown piece of code allocation of vp isn't obvious. I miss a line like
vp = (char**)malloc(n*sizeof(char*));
or the like after the fscanf(fin,"%d", &n) and before the loop.

However, are you sure that n is given in a textual representation in the file? Are you furthur sure that any line read by fscanf(fin,"%s", buffer) doesn't overflow the buffer?

thank you for the quick response. it works now. on the first line of the file is "n", of that i am sure. also i am sure the buffer is not overflowed.