Programming

I am compiling little codes and I am receiving formatting errors. Can anyone tell me the problems and how would I fix it?

1.

Code:

int main()
{
        int n;
        printf( "Enter an integer => " );
        scanf( "%d", n );
        printf( "%d\n", n );
}

bug1.c:7:2: warning: format â%dâ expects argument of type âint *â, but argument 2 has type âintâ [-Wformat]

Is this reading the input number as a string so it is giving an error?

2.

Code:

int main()
{
        int n = 1;
        double pi = M_PI;
        printf("Pi=%d, n=%f\n", pi, n);
}

bug2.c:8:2: warning: format â%dâ expects argument of type âintâ, but argument 2 has type âdoubleâ [-Wformat]
bug2.c:8:2: warning: format â%fâ expects argument of type âdoubleâ, but argument 3 has type âintâ [-Wformat]

3.

Code:

double avg(double a[], int n)
{
        int i;
        double sum;

        assert(n > 0);
        sum = 0.0;
        for (i=0;i<n;i++)
                sum += a[i];
        return sum/n;
}

int main()
{
        double a[5] = {1.0,2.0,3.0,4.0,5.0};
        int n;

        printf("Enter size:  ");
        scanf("%d",n);
        assert(n<5);
        printf("Avg. = %f\n",avg(a,n));
}

avg.c:22:2: warning: format â%dâ expects argument of type âint *â, but argument 2 has type âintâ [-Wformat]

Thank you for any help

Did you read the man page for scanf?

So for the first one, I think I figured out the problem. It needs a pointer of the specified type.

But I am still stuck on the other two.

The compiler is telling you exactly what's wrong in all of these cases.