Compilare: main.cpp: In function 'int main()': main.cpp:160:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0 ; j < v[i].size() ; j++){ ~~^~~~~~~~~~~~~ main.cpp:106:45: warning: unused variable 'ev' [-Wunused-variable] int m, n , f, dy , i , x, y , x2 , y2 , ev=0 , cost , j; ^~ main.cpp:109:37: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread (buff , 1 , 5000000 , fin); ^ main.cpp:173:13: warning: 'y' may be used uninitialized in this function [-Wmaybe-uninitialized] fprintf (fout,"%d %d %d %d", x - dx , y - dy , x , y); ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~