double abstr (double x)
{
    if(x<0.0)
    x=-x;
    else
    x=x;
    return (x);
    }
#include <stdio.h>
int main(void)
{
    double a,abstr(double a);
    printf("enter areal number please:");
    scanf("%1f",&a);
    printf("abstr(%1f)=%1f\n",a,abstr(a));
    return 0;
    }