Compilare: user.cpp: In function ‘char nextch()’: user.cpp:10:31: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buf,1,MAXBUF,fi); ^ user.cpp: In function ‘int main()’: user.cpp:149:12: warning: ‘X1’ may be used uninitialized in this function [-Wmaybe-uninitialized] X2=X1+dx; ^