Some Tips for Writing C/C++ Programs

  Here in this post I am discussing a few points to note while writing C/C++ programs. These points might help you reduce errors while writing programs and also makes them easy to debug.

• Be careful while using the == (Relational Operator) and = (Assignment) operators. So many errors were made because of these two operators. Consider the code given below. It will not show any error.                              

                              if(x=1)

                              {
                                   printf("\nHello");
                              }

                      The actual code intended was the one given below.
                              if(x=1)                              
                              {
                                   printf("\nHello");
                              }               
  
                      But if you change the code as follows, it will show an error if you forget an equal to sign.
                              if(1==x)
                              {
                                   printf("\nHello");
                              }
                      Here if you forget an equal to sign, you will get the following error "lvalue required".

• Always use ++ and -- operators on lines by themselves. Avoid statements like arr[++i] as you may not get the intended side effect. 

•  Try to have a default statement in every switch statement, even if it is not doing anything.

• Put parentheses around each constant expression defined by the pre-processor #define directive.

                              #define EQN(x,y)  x*y 

                       EQN(5+6) will give you 41 output instead of the intended 121.

                       The correct statement is shown below.

                              #define EQN(x,y)  (x)*(y)

• Never do nothing silently. For example consider the code given below. It was included in the program to bring some delay.

                              for(i=0;i<10000;i++) ; // Note the semi colon.                         
                        A better code is shown below.
                              for(i=0;i<10000;i++)
                               /* Do Nothing, Just for Delay */ ;
                        This will make debugging easier at a later stage.

• The upper & lower limit of data types in C/C++ is often dependent on the compiler. To verify the limits of data types in your compiler check the header file limits.h.

• Beware of Semi Colons in your program.

• If statements in your program contains operators with different precedence, then using brackets is a very good idea.