Blah blah

#include <stdio.h>
#include <math.h>
#include <string.h>
#define G 9.8
#define PI M_PI

float degrees(float theta);
float radians(float theta);
float minTheta(float v, float d);
float angle(float v, float h, float d);

int main(){

  float v, h, d, theta;
  char choice[20];

  printf("Compute: distance or angle? ");
  scanf("%s", choice);

  if((strstr(choice, "d") > 0) || (strstr(choice, "D") > 0)){ //broken enter choice
    printf("Enter: speed height angle: ");
    scanf("%f%f%f", &v, &h, &theta);

    theta = radians(theta); //runs radians function to convert input to radians.

    d = ((v*cos(theta))*(v*sin(theta)+(sqrt(pow(v,2)*pow(sin(theta),2)-(float)2*G*h))))/G;
    if(isnan(d)){ //MAKE FUNCTION???
      printf("no solution");
    }
    else{
      printf("distance is %.2f metres", d);
    }
  }
  else if((strstr(choice, "a") > 0) || (strstr(choice, "A") > 0)){
      printf("Enter: speed height distance: ");
      scanf("%f%f%f", &v, &h, &d);

      theta = angle(v, h, d);
      if(theta == 0){
    printf("no solution");
      }
      else{
      printf("angle is %.2f degrees", theta);
      }
  }
  return 0;
}

//function to convert degrees to radians for use in trig functions.
float radians(float theta){

  theta = theta * PI/180;

  return theta;
}

//computes the lower limit of theta given by arctan(v^2/g*h) returns answer in radians.
float minTheta(float v, float d){
  float theta;
  float tmp;

  tmp = (pow(v,2))/(G*d);

  theta = atan(tmp);

  return theta;
}

//function to convert radians to degrees for displayed output
float degrees(float theta){
  theta = theta * (180/(PI));
  return theta;
}

//calulates theta by trial and error
float angle(float v, float h, float d){

  float dif;
  float trial;
  float theta;

  theta  = minTheta(v, d);

  while(theta <= ((PI)/2)){
    trial = ((v*cos(theta))*(v*sin(theta)+(sqrt(pow(v,2)*pow(sin(theta),2)-(float)2*G*h))))/G;

    dif = fabsf((d - trial));

    if(dif < 0.0001){ //since answer only needs to be 2 decimal places, this tolerence is justified.
      theta = degrees(theta);
      return theta;
    }
      theta = theta + 0.000001;
  }
  return 0;
}