Question

#include<stdio.h>

int main()
{
    int x;
    float peri ,area1;
    scanf("%d",&x);
    area(x, &peri, &area1);
    printf(" %f %f ", peri, area1);
    return 0;
}

int area(int r, float *per, float *are)
{
    *per = 2.0 * r;
    *are = 3.14 * r * r;
}

This works fine but when I try to change the input value to float

#include<stdio.h>

int main()
{
    float x, peri, area1;
    scanf("%f",&x);
    float area(x, &peri, &area1);
    printf(" %f %f ", peri, area1);
    return 0;
}

float area(float r, float *per, float *are)
{
    *per = 2.0 * r;
    *are = 3.14 * r * r;
}

I get:

error: expected ‘)’ before ‘&’ token

Answer 1

 float area( x, &peri, &area1);

should be

area( x, &peri, &area1);

You don’t need to specify the return type when you are calling the function.

Also since the return type now is non-int you need to either:

1. Move the function definition before main.

2. Provide a function declaration like:

   float area(float, float *, float *);
   

   before main.

Also since you are not returning anything from the function you should be making its return type as void.