Compilare: user.cpp: In function ‘char nextch()’: user.cpp:12:36: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buf, BUF_SIZE, 1, fi); ^ user.cpp: In function ‘int main()’: user.cpp:87:23: warning: iteration 40u invokes undefined behavior [-Waggressive-loop-optimizations] if(pr[i][j]==1) ^ user.cpp:86:9: note: containing loop for(int j=1;j<1700;j++) ^