Compilare: user.cpp: In function ‘int main()’: user.cpp:103:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int p = 1; p < A[i].size(); p++){ ^ user.cpp:55:42: warning: unused variable ‘x’ [-Wunused-variable] int n = nextnum(), m = nextnum(), k, x; ^ user.cpp: In function ‘char nextch()’: user.cpp:11:36: 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); ^