Compilare: main.cpp: In function 'int Test(char*)': main.cpp:18:56: warning: converting to non-pointer type 'char' from NULL [-Wconversion-null] else {if(a[m-1]=='(') {a[m-1]=NULL; m--;} ^~~~ main.cpp:24:56: warning: converting to non-pointer type 'char' from NULL [-Wconversion-null] else {if(a[m-1]=='[') {a[m-1]=NULL; m--;} ^~~~ main.cpp: In function 'int main()': main.cpp:46:50: warning: converting to non-pointer type 'char' from NULL [-Wconversion-null] else if(b[j]=='*') {if(m!=0) {a[m-1]=NULL; m--;}} ^~~~ main.cpp:47:38: warning: converting to non-pointer type 'char' from NULL [-Wconversion-null] else if(b[j]=='E') {a[m]=NULL; ^~~~