radians degrees

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif

double toDegrees(double dAngleRadians) {
    return dAngleRadians * 180.0 / M_PI;
}

double toRadians(double dAngleDegrees) {
    return dAngleDegrees * M_PI / 180.0;
}

int main (int argc, char **argv){


    double dDegrees, dRadians;

    dDegrees = 90.0;

    printf("Degrees: %f\n",dDegrees);

    dRadians = toRadians(dDegrees);

    printf("Radians: %f\n",dRadians);

    dDegrees = toDegrees(dRadians);

    printf("Degrees: %f\n",dDegrees);

return 0;
}

/*
output:

Degrees: 90.000000
Radians: 1.570796
Degrees: 90.000000

*/