View Compilation Error

0_0_29685719_30048.cpp: In function 'int main()':
0_0_29685719_30048.cpp:51:4: error: 'cout' was not declared in this scope
    cout<<s1<<" + "<<s2<<" = ";
    ^
0_0_29685719_30048.cpp:58:21: error: 'endl' was not declared in this scope
    if(i!=n-1) cout<<endl;
                     ^