Code: float *u; printf("here %d\n", n); if ( !( u = (float *)calloc (2*n,sizeof (float)) )) printf( "calloc failed\n"); printf("2here\n"); The first print statement tells me that n is 175;neither calloc failed or 2here is printed. The code compiles but I get a checksum error for freed pointer when I run. Just a clue as to what's going on or how to debug this. Thanks.