Compilare: main.cpp: In function 'int main()': main.cpp:20:14: warning: comparison of integer expressions of different signedness: 'int' and 'size_t' {aka 'long unsigned int'} [-Wsign-compare] 20 | for(i=0;i<strlen(c);i++) | ~^~~~~~~~~~ main.cpp:37:14: warning: comparison of integer expressions of different signedness: 'int' and 'size_t' {aka 'long unsigned int'} [-Wsign-compare] 37 | for(i=0;i<strlen(c);i++) | ~^~~~~~~~~~ main.cpp:58:25: warning: converting to non-pointer type 'char' from NULL [-Wconversion-null] 58 | c2[cnt]=NULL; | ^~~~ main.cpp:103:26: warning: comparison of integer expressions of different signedness: 'int' and 'size_t' {aka 'long unsigned int'} [-Wsign-compare] 103 | for(k=0;k<strlen(mat[j]);k++) | ~^~~~~~~~~~~~~~~