Compilare: user.cpp: In function ‘int main()’: user.cpp:26:33: warning: format ‘%s’ expects argument of type ‘char*’, but argument 4 has type ‘char (*)[260]’ [-Wformat=] scanf("%d %d %s\n",&x,&y,&ss); strcat(ss,"+"); ^ user.cpp:29:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0;j<s.length();j++){ ^ user.cpp:45:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<l.size();i++) ^ user.cpp:48:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0;j<a.size();j++){ ^ user.cpp:56:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0;j<a.size();j++) ^ user.cpp:22:28: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("mxl.in","r",stdin); ^ user.cpp:23:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("mxl.out","w",stdout); ^ user.cpp:24:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:26:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %s\n",&x,&y,&ss); strcat(ss,"+"); ^