Compilare: main.cpp: In function 'int evaluate(char*)': main.cpp:31:23: warning: comparison of integer expressions of different signedness: 'int' and 'size_t' {aka 'long unsigned int'} [-Wsign-compare] 31 | for (int i = 0; i < strlen(tokens); i++) { | ~~^~~~~~~~~~~~~~~~ main.cpp:34:44: warning: comparison of integer expressions of different signedness: 'int' and 'size_t' {aka 'long unsigned int'} [-Wsign-compare] 34 | while (isdigit(tokens[i]) && i < strlen(tokens)) { | ~~^~~~~~~~~~~~~~~~ main.cpp: In function 'int calculate(int, int, char)': main.cpp:21:1: warning: control reaches end of non-void function [-Wreturn-type] 21 | } | ^