Compilare: main.cpp: In function 'void stronglyConnected(int)': main.cpp:34:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<arcs[current_node].size(); ++i) ~^~~~~~~~~~~~~~~~~~~~~~~~~~ main.cpp: In function 'void stronglyConnectedBackArcs(int)': main.cpp:45:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<back_arcs[current_node].size(); ++i) ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.cpp: In function 'void computeComponents()': main.cpp:64:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j<stronglyConnectedOrder.size(); ++j) ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.cpp: In function 'void calculateComponentsDegs()': main.cpp:82:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j<arcs[i].size(); ++j) ~^~~~~~~~~~~~~~~ main.cpp: In function 'void componentsBFS()': main.cpp:92:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<allComponents.size(); ++i) ~^~~~~~~~~~~~~~~~~~~~~ main.cpp:99:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<allComponents[current_component].size(); ++i) { ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.cpp:106:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j<arcs[current_variable].size(); ++j) { ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:120:32: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("2sat.in", "r", stdin); ^ main.cpp:121:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("2sat.out", "w", stdout); ^ main.cpp:124:23: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ main.cpp:126:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &a, &b); ^