c - cannot understand this error

Question

As I am a beginner in C

When I run the following C code :

#include<stdio.h>

void f(int *p)
{
    *p=3;
}

int main()
{
    int *p;
    f(&p);
    return 0;
}

I get these messages after compilation:

1) warning:passing arg 1 of 'f' from incompatible pointer type f(&p)

2) note: expected 'int *' but argument is of type 'int **' void f(int *p)

Answer 1

Please note:

&p is the memory address of a variable

*p is the actual value of the variable

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So what you are doing is:

In main: You are generating a variable pointer p. And you are passing this pointers address to a function f.

f thinks it gets a pointer as parameter but it gets a memory address and obviusly can't handle it.

More information is here

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Hope I could help!