Compilare: main.cpp:5:79: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type] using namespace std;ifstream f("royfloyd.in");ofstream o("royfloyd.out");main(){int n,i,j,k,c[b][b];f>>n;c(i)c(j){f>>c[i][j];if(i!=j&!c[i][j])c[i][j]=a;}c(k)c(i)c(j)c[i][j]=min(c[i][j],c[i][k]+c[k][j]);c(i){c(j)if(c[i][j]==a)o<<0<<" ";else o<<c[i][j]<<" ";o<<'\n';}} ^ main.cpp: In function 'int main()': main.cpp:5:130: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses] using namespace std;ifstream f("royfloyd.in");ofstream o("royfloyd.out");main(){int n,i,j,k,c[b][b];f>>n;c(i)c(j){f>>c[i][j];if(i!=j&!c[i][j])c[i][j]=a;}c(k)c(i)c(j)c[i][j]=min(c[i][j],c[i][k]+c[k][j]);c(i){c(j)if(c[i][j]==a)o<<0<<" ";else o<<c[i][j]<<" ";o<<'\n';}} ~^~~