echitabil.cpp: In function `int main()': echitabil.cpp:16: warning: comparison between signed and unsigned integer expressions echitabil.cpp:22: warning: comparison between signed and unsigned integer expressions echitabil.cpp:24: warning: comparison between signed and unsigned integer expressions echitabil.cpp:25: warning: comparison between signed and unsigned integer expressions echitabil.cpp:26: warning: comparison between signed and unsigned integer expressions echitabil.cpp:40: warning: comparison between signed and unsigned integer expressions