C言語のさまざまな部分を説明する

/* documentation section */
preprocessor directives
global declaration
main ( ){
   local declaration
   executable statements
}
returntype function name (argument list){
   local declaration
   executable statements
}

#include<stdio.h>
void main(){
   //Function declaration - (function has void because we are not returning any values for function)//
   void sum(int,int);
   //Declaring actual parameters//
   int a,b;
   //Reading User I/p//
   printf("Enter a,b :");
   scanf("%d,%d",&a,&b);
   //Function calling//
   sum(a,b);
}
void sum(int a, int b){//Declaring formal parameters
   //Declaring variables//
   int add;
   //Addition operation//
   add=a+b;
   //Printing O/p//
   printf("Addition of a and b is %d",add);
}

Enter a,b :5,6
Addition of a and b is 11