# Parameters & Return Values — C Programming

Source: https://www.geekswithgeeks.com/en/c/c-function-params-return

> How data flows into and out of a function.

## Parameters are local copies

When you call `add(3, 4)`, the values `3` and `4` are copied into the parameters `a` and `b`. Changing `a` inside the function never affects the caller's variable.

## Multiple return paths

A function can `return` from more than one place; execution stops at the first one reached.

```c
int sign(int n) {
    if (n > 0) return 1;
    if (n < 0) return -1;
    return 0;
}
```

## Only one value out

`return` sends back exactly one value. To get multiple results out, use pointers (parameters) or return a struct.