C Programming - Functions - Discussion

The prototype is not defined how will program work is it possible?

Can anyone explain this program?

Please.

Actually when we write return (a, b); then this values first go into the stack so a will go at 0th position and b will go at the 1th position. And stack follows the LIFO criteria that's why the last element will be returned i.e. b.

In return(kk,LL).

The value of LL will be return only commo operation rule.

Step 1: int i=3, j=4, k, l; The variables i, j, k, l are declared as an integer type and variable i, j are initialized to 3, 4 respectively.

The function addmult(i, j); accept 2 integer parameters.

Step 2: k = addmult(i, j); becomes k = addmult(3, 4)

In the function addmult(). The variable kk, ll are declared as an integer type int kk, ll;

kk = ii + jj; becomes kk = 3 + 4 Now the kk value is '7'.

ll = ii * jj; becomes ll = 3 * 4 Now the ll value is '12'.

return (kk, ll); It returns the value of variable ll only.

The value 12 is stored in variable 'k'.

Step 3: l = addmult(i, j); becomes l = addmult(3, 4)
kk = ii + jj; becomes kk = 3 + 4 Now the kk value is '7'.
ll = ii * jj; becomes ll = 3 * 4 Now the ll value is '12'.
return (kk, ll); It returns the value of variable ll only.
The value 12 is stored in variable 'l'.

Step 4: printf("%d, %d\n", k, l); It prints the value of k and l

Hence the output is "12, 12".

The answer is 12.

Here return (kk, ll); it will return only kk as RETURN only return one value i.e first one.

Thanks for the explanation @Sundar.

Comma (,) Operator has LEFT to RIGHT associativity rules, so if we assign/return a VARIABLE a list of values with comma then it takes the RIGHT most value.

In this program, there are two errors.

1. We cannot return two value at a function.

2. Declaration of the function is not available.

Because of this, it is compile time error.