Function - C P P

• Theory
• Syntax

Theory

• Function Call Stack => LIFO
• Scope => Variable can only be accessed inside that Block
• Types
  • Inline Function
    • Used to reduce the function calls overhead

          inline returnType functionName(dataType& var1) {
              return var2;
          }
      

    • Should be 1 line, Compiler decides if 2 or 3 lines, Not for more than 3 lines
    • Replaces code just like Macro
  • Const function
    • For const return type

          const returnType functionName(dataType var1) {
              return var2;
          }
      

    • For const return type and const parameter

          const returnType functionName(const dataType var1) {
              return var2;
          }
          // Const value needs to be passed
          const dataType variable = value;
          functionName(variable)
      

• Return by Reference, Bad Practice, Local variable is being sent

      int& functionName(int var) {
          int num = a;
          int& ans = num;
          return ans;
      }
  

Syntax

• Function

    returnType functionName(argument var1) {
      // Statement
      return var2;
    }
  

• Function with default parameter, Default should always be the right-most argument

    returnType functionName(dataType=value) {
      // statement
    }
  

• Calling a Function
  • Pass by Value, Copy is created

        returnType functionName(int var) {
            // statement
        }
        functionName(var);
    

  • Pass by Reference, Using reference variable, No new memory is created

        returnType functionName(int& var) {
            // statement
        }
        functionName(var);