im trying to find the largest number from a selected row of an matrix. My code is ok until i insert negative numbers. I don't know what to write for solvinng this...

#include<iostream> #include<cstdlib> using namespace std; int main () { int rang=10,i,j, M[rang][rang],n,k,max=0; char answer; do{ do{cout<<"Insert the matrix rank(max. 10): "; cin>>n; } while(n<1||n>rang); cout<<"Insert elements: "<<endl; for(i=0;i<n;i++) for(j=0;j<n;j++){cout<<"M["<<i<<"]["<<j<<"]= "; cin>>M[i][j];} cout<<endl; for(int i=0; i<n;i++){ for(int j=0;j<n;j++) cout<<"\t"<<M[i][j]; cout<<"\n\n";} do{ cout<<"Select a row: "; cin>>k;} while(k<0||k>n); for(j=0;j<n;j++) if (max<M[k-1][j]){max=M[k-1][j];} cout<<"The largest number of the "<<k<<" row is "<<max<<endl ; cout << "Try again? (Y/N): "; cin >> answer; cout << endl; } while(answer == 'Y' || answer == 'y'); }