Main.cc: In function ‘int main()’:
Main.cc:4:24: error: ‘sum’ was not declared in this scope
int n,a[101][101],k=1;sum=0;
^~~
Main.cc:4:20: warning: unused variable ‘k’ [-Wunused-variable]
int n,a[101][101],k=1;sum=0;
^