Main.cc: In function ‘int main()’: Main.cc:6:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i='a'&&a[i]<='z')a[i]-=32; ~^~~~~~~~~~~ Main.cc:6:34: error: ‘a’ was not declared in this scope for(int i=0;i='a'&&a[i]<='z')a[i]-=32; ^ Main.cc:7:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i='a'&&a[i]<='z')a[i]-=32; ~^~~~~~~~~~~ Main.cc:7:34: error: ‘a’ was not declared in this scope for(int i=0;i='a'&&a[i]<='z')a[i]-=32; ^ Main.cc:8:20: error: ISO C++ forbids comparison between pointer and integer [-fpermissive] if(strcmp(n1,n2)==n1&&strcmp(n1,n2)!=n2)cout<<">"; ^~ Main.cc:8:39: error: ISO C++ forbids comparison between pointer and integer [-fpermissive] if(strcmp(n1,n2)==n1&&strcmp(n1,n2)!=n2)cout<<">"; ^~ Main.cc:9:25: error: ISO C++ forbids comparison between pointer and integer [-fpermissive] else if(strcmp(n1,n2)!=n1&&strcmp(n1,n2)==n2)cout<<"<"; ^~ Main.cc:9:44: error: ISO C++ forbids comparison between pointer and integer [-fpermissive] else if(strcmp(n1,n2)!=n1&&strcmp(n1,n2)==n2)cout<<"<"; ^~