Thread: how this C working?

So which bit is confusing you?
- how to read the input
- how to make a decision on that input
- how to do the maths

You've got to show us something first, we're not here to hand out answers on demand (see the forum rules).

You should be more specific or/and show part of your code concerning the problem. May be you mean a menu to select operation...then I suggest this:

Code:

// function declarations goes here

int main()
{
int selection=0;
do
{
 selection=menu(); //access function menu to get operation

if (selection==1)
//area of square
else
if(selection==2)
//area of rectangle

//note that it is better if your create another function
//to tackle the area operation.
.
.
.

}while( selection!=3 );
 
return 0;
}


int menu()
{
 int choice=0;
 do
     {
      printf("\n\nMENU\n_______\n\n");
      printf("1.Area of square\n2.Area of rectangle\n3.Exit");
      printf("\n\nEnter selection number: ");

      scanf("%d",&choice);
      
         if ((choice==1)||(choice==2)||choice==3)
           return choice;
      
         else
         {
           printf("\n\nInvalid Request!\n");
           choice=0;
         }
     }
     while(choice==0);
}

Or use a switch statement instead of else if's but that is style issue really