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Question

Given the above information, write a string function named RootDistance() that takes three double parameters that represent the coefficients of a quadratic function in descending order (a, b and c in that order). If the quadratic function has at least one real root, the function returns the distance between the roots as a string; otherwise, the function returns the string 'no roots'. Use the functions sqrt () from the Cmath library and to string() from the string library to calculate the square root and convert a double to a string respectively. For instance, the calls RootDistance(1,-6,9), Root Distance(10,-1,-2) and RootDistance(1,0,1) will return '0', '0.9' and 'no roots' respectively. 

Answer 1

#include <stdio.h>

#include <string.h>

#include <math.h>

#include <stdlib.h>

#define OUTBUFF_SIZE (255)

char * RootDistance( double A, double B, double C)

{

double discriminant = B*B - 4*A*C;

char outbuff[OUTBUFF_SIZE];

if (discriminant<0)

{

strcpy(outbuff,"NO ROOTS");

}

else if (A==0)

{

strcpy(outbuff,"0");

}

else

{

double root1 = (-B + sqrt(discriminant))/(2*A);

double root2 = (-B - sqrt(discriminant))/(2*A);

//algebraically the same as sqrt(discriminant)/A

sprintf(outbuff,"%6.2f", fabs(root1-root2));

}

int N = strlen(outbuff);

char * buffReturn = (char*)malloc(N);

strcpy(buffReturn,outbuff);

return(buffReturn);

}

int main()

{

char * buff;

printf("%s \n",(buff = RootDistance(1,-6,9))); free(buff);

printf("%s \n",(buff=RootDistance(10,-1,-2))); free(buff);

printf("%s \n",(buff=RootDistance(1,0,1))); free(buff);

}