Question

how can i write a function to call by reference ? using fopen, printf, fclose statements.

#define _CRT_SECURE_NO_WARNINGS
#define PI 3.14159
#include <stdio.h>

void findArea(double *area, double r);

int main(void) {
         double area, r = 100.5;
         findArea(&area, r);
         printf("area = %.2lf\n", area);
         return 0;
}

Answer 1

#define _CRT_SECURE_NO_WARNINGS

#define PI 3.14159

#include <stdio.h>

void findArea(double *area, double r);

int main(void) {

double area, r = 100.5;

findArea(&area, r);

printf("area = %.2lf\n", area);

return 0;

}

void findArea(double *area,double r){

*area=PI*r*r;

}

#using file fopen and fclose

data.txt

100.5