I changed a code so that it could accept floats in a void pointer cast and use it in a function but while it was working with ints before making adjustment to it made the "incompatible types when assigning to type 'float' from type 'void *'" after I changed it to floats, could some one help where am I making a mistake?
#include <stdio.h>
void * square (const void *num);
int main() {
float x, sq_int;
x = 6.543;
sq_int = square(&x);
printf("%f squared is %f\n", x, sq_int);
return 0;
}
void* square (const void *num) {
static float result;
result = (*(float *)num) * (*(float *)num);
return(result);
}
The problem line is
sq_int = square(&x);
because square
returns void*
as well.
You need to handle the return of square
either by returning a pointer to the result, like
return &result;
and in main extract it as:
sq_int = *(float *)square(&x);
Which is a bad idea since you're accessing a variable that is no longer on the stack.
Or better, by storing it in the heap first, like
void* square (const void *num) {
float *result = malloc(sizeof(float));
*result = (*(float *)num) * (*(float *)num);
return result;
}
and in main extract it as:
sq_int = *(float *)square(&x);
But do remember to free up the allocation before exiting.
You need to do two things.
Cast the return type:
sq_int = *(float*) square(&x);
Return the address of result
.
return &result;
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