Compilare: main.cpp: In function 'void answer(int)': main.cpp:34:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (ret + step < positions[value].size() && positions[value][ret + step] <= elements) { ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:46:33: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d\n", &querys) ; ^ main.cpp:49:46: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d %d\n", &type, &value) ; ^