开发者_如何学Python

how to return more than one value from a function?

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A function can only have a single return value. You could either pack multiple values into a compound data type (e.g. a struct), or you could return values via function parameters. Of course, such parameters would have to be passed using pointers to memory declared by the caller.

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1

Declare method like this foo (char *msg, int *num, int *out1, int *out2); and call it like this

int i=10;
char c='s';
int out1;
int out2;
foo(&c,&i,&out1,&out2);

Now what ever values u assign to out1 and out2 in function will be available after the function returns.

2

Return a structure having more than one members.

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In C, one would generally do it using pointers:

int foo(int x, int y, int z, int* out);

Here, the function returns one value, and uses out to "return" another value. When calling this function, one must provide the out parameter with a pointer pointing to allocated memory. The function itself would probably look something like this:

int foo(int x, int y, int z, int* out) {
    /* Do some work */
    *out = some_value;
    return another_value;
}

And calling it:

int out1, out2;
out1 = foo(a, b, c, &out2);

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You cannot return more than 1 value from a function. But there is a way. Since you are using C, you can use pointers.

Example:

// calling function:
foo(&a, &b);
printf("%d %d", a, b);
// a is now 5 and b is now 10.

// called function:
void foo(int* a, int* b) {
   *a = 5;
   *b = 10;
}

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Functions can return arrays or lists