Compilare: main.cpp: In function 'int main()': main.cpp:236:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = 0; j + 1 < nodes.size(); j++) { ~~~~~~^~~~~~~~~~~~~~ main.cpp:261:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(edges.size() >= n || all_nodes.size() > 4 * n || all_edges.size() > 4 * n) { ~~~~~~~~~~~~~^~~~ main.cpp:261:50: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(edges.size() >= n || all_nodes.size() > 4 * n || all_edges.size() > 4 * n) { ~~~~~~~~~~~~~~~~~^~~~~~~ main.cpp:261:78: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(edges.size() >= n || all_nodes.size() > 4 * n || all_edges.size() > 4 * n) { ~~~~~~~~~~~~~~~~~^~~~~~~ main.cpp: In function 'char nextch()': main.cpp:15:34: 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); ^