Tmp2

Good practice in Coding (in C++/C)

Keep complications to minimum

• Use pointers sparingly, there are many situations where they have good alternatives. Make a concious effort to find these alternatives if at all possible. One good example is use of vectors instead of dynamic arrays.

int* a = NULL;   // Pointer to int, initialize to nothing.
int n;           // Size needed for array
cin >> n;        // Read in the size
a = new int[n];  // Allocate n ints and save ptr in a.
for (int i=0;i<n;i++){
    cin >> a[i];
}
...
... 
delete [] a;  // When done, free memory pointed to by a.
a = NULL;     // Clear a to prevent using invalid memory reference.

vector <int> a; int n; // Size needed for array cin >> n; // Read in the size for (int i=0;i<n;i++){ int tmp; cin >> tmp; a.push_back(tmp); |} ... ... a.erase(); // When done, free memory pointed to by a.

Variables

• Define variables with minimum scope. If you just need a variable to use for a counter in a loop, don't define it as a global variable. In for loops define the counter within the for statement.

for(unsigned int i=0;i<vect.size();i++){ // much better than a globally defined i. 
   ...
}

Loops

• For loops without braces are sometimes possible. But do a favor, don't do it!

for (int i=0;i<n;i++)
    // foo
    // bar
    cout << str[i]; // perfrectly correct, loop ends here. BUT CONFUSING. 
c=a+b
..
..

for (int i=0;i<n;i++){
    // foo
    // bar
    cout << str[i];
} //much better way. 
c=a+b
..
..

• Use indenting and comments to make multiple loops easy to read. In long loops like the code shown below it really helps to have the comments like end of loop i at the place where the loop is closed.

for (int i=0;i<n;i++){
   for (int j=0;j<m;j++){
       a=b[i];
       //... 559 lines of code -- we don't print them here
   } // end of loop j
   //... another 400 lines of code -- again we skip. 
} // end of loop i