Compilare: main.cpp: In function 'void calc2()': main.cpp:9:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=m;j<=r;j+=m) ~^~~ main.cpp:13:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<=r;i++) ~^~~ main.cpp: In function 'void calc3()': main.cpp:24:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=m;j<=r;j+=m) ~^~~ main.cpp:28:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<=r;i++) ~^~~ main.cpp: In function 'void calc5()': main.cpp:39:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=m;j<=r;j+=m) ~^~~ main.cpp:43:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<=r;i++) ~^~~ main.cpp: In function 'int main()': main.cpp:61:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int c=0;c<=r;c++) ~^~~