Compilare: user.cpp: In function ‘void radix_sort()’: user.cpp:20:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<cifre[i].size();++j)x[++n] = cifre[i][j]; ^ user.cpp: In function ‘int main()’: user.cpp:38:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<x.size();i+=10)printf("%d ",x[i]); ^ user.cpp:30:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("radixsort.in","r",stdin); ^ user.cpp:31:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("radixsort.out","w",stdout); ^ user.cpp:32:37: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d",&n,&a,&b,&c); ^