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

/*
delta-G - J/mol K
Formula - Name            -   Delta-G
N2O     - Nitrous Oxide   -    103.7 (gas)
C3H8    - Propane         -    -23.4 (gas)
CO2     - Carbon Dioxide  -   -394.4 (gas)
H2O     - Water           -   -228.6 (gas)
N2      - Nitrogen        -    0
*/

int H2  = 0;
int H2O = 1;
int CO  = 2;
int CO2 = 3;
int O2  = 4;
int N2  = 5;

int N2O = 6;
int C3H8 = 7;

float dG[10];
/* Table comes from page 170 of Space Propulsion Analysis and Design 
   First index times 100 is temp Kelvin 
   Second index are first 6 chemical compounds above
   */
float Enthalpy[41][6]=
/* 0 */      {{0.0, 0.0, 0.0, 0.0, 0.0, 0.0},
             {0.0, 0.0, 0.0, 0.0, 0.0, 0.0},
             {0.0, 0.0, 0.0, 0.0, 0.0, 0.0},
/* 300 */    {0.0, 0.0, 0.0, 0.0, 0.0, 0.0},
             {2.909, 3.395, 2.926, 3.943, 3.018, 2.918},
/* 500 */   {5.831, 6.869, 5.877, 8.246, 6.057, 5.856},
	   {8.761, 10.448, 8.895, 12.859, 9.222, 8.841},
  	   {11.704, 14.149, 11.980, 17.715, 11.851, 11.888},
  	   {14.659, 17.966, 15.132, 22.776, 15.815, 14.994},
  	   {17.631, 21.910, 18.360, 28.013, 19.230, 18.180},
 /* 1000 */ {20.641, 25.987, 21.646, 33.388, 22.692, 21.424},
           {23.68,  30.185, 25.003, 38.892, 26.280, 24.727},
           {26.761, 34.522, 28.402, 44.493, 29.867, 28.084},
           {29.880, 38.980, 31.839, 50.186, 33.446, 31.479},
           {33.048, 43.530, 35.317, 55.954, 37.034, 34.920},
           {36.628, 48.219, 38.825, 61.785, 40.621, 38.398},
           {39.512, 52.995, 42.362, 67.679, 44.338, 41.898},
           {42.806, 57.858, 45.929, 73.619, 48.059, 45.435},
           {46.142, 62.815, 49.516, 79.605, 51.777, 48.989},
           {49.512, 67.838, 53.116, 85.625, 55.494, 52.568},
 /* 2000 */ {52.928, 72.937, 56.737, 91.682, 59.215, 56.164},
            {56.369, 78.106, 60.375, 97.776, 63.045, 59.772},
            {59.839, 83.339, 64.021, 103.896, 66.867, 63.388},
            {63.343, 88.622, 67.683, 110.050, 70.697, 67.030},
            {66.871, 93.959, 71.350, 116.203, 74.519, 70.672},
            {70.438, 99.346, 75.026, 122.407, 78.349, 74.335},
            {74.021, 104.780, 78.726, 128.632, 82.293, 78.010},
            {77.617, 110.251, 82.426, 134.864, 86.236, 81.694},
            {81.250, 115.768, 86.131, 141.118, 90.179, 85.390},
            {84.900, 121.310, 89.848, 147.393, 94.126, 89.095},
/* 3000 */  {88.578, 126.899, 93.570, 153.676, 98.065, 92.804},
            {92.264, 132.520, 97.291, 159.997, 102.071, 96.521},
            {95.972, 138.163, 101.033, 166.326, 106.090, 100.242},
            {99.702, 143.839, 104.767, 172.647, 110.125, 103.968},
            {103.444, 149.536, 108.514, 179.010, 114.177, 107.702},
            {107.208, 155.267, 112.260, 185.360, 118.242, 111.440},
            {110.979, 161.019, 116.015, 191.752, 122.311, 115.182},
            {114.763, 166.791, 119.774, 198.132, 126.409, 118.933},
            {118.573, 172.593, 123.537, 204.536, 130.511, 122.679},
            {122.759, 178.403, 127.305, 210.949, 134.638, 126.438},
            {126.220, 184.226, 131.076, 217.379, 138.778, 130.201}};


/* 10-N2O + 1 C3H8 => 10-N2 + 3-CO2 + 4-H2O   */

main()
{
float reactants, products, deltaG;
float temp, Qreq, lastQ;
int Ti;  /* Temp Index */
float diff, scale, extra, portion, deltaT;

dG[N2O]= 103.7;
dG[C3H8]= -23.4;
dG[CO2]= -394.4;
dG[H2O] = -228.6;
dG[N2] = 0;        

reactants = 10 * dG[N2O] + 1*dG[C3H8];
products = 10 * dG[N2] + 3* dG[CO2] + 4 * dG[H2O];
deltaG = abs(reactants - products);

printf("reactants %f   products %f   net energy %f \n",
        reactants, products, deltaG);

printf("Enthalpy[20][H2O] %f  \n", Enthalpy[20][H2O]);
printf("Enthalpy[35][CO2] %f  \n", Enthalpy[35][CO2]);
Qreq=0;
Ti = 3;
while (Qreq < deltaG) {
  lastQ=Qreq;
  Ti++;
  temp=Ti*100;
  Qreq = 10 * Enthalpy[Ti][N2] + 3 * Enthalpy[Ti][CO2] + 4 * Enthalpy[Ti][H2O];
}

scale = Qreq-lastQ;
extra = deltaG - lastQ;
portion = extra/scale;
temp = 100.0 * (Ti-1 + portion);

printf("Ti %d  \n", Ti);
printf("Qreq %f  lastQ %f  \n", Qreq, lastQ);
printf("scale %f  extra %f  \n", scale, extra);
printf("portion %f  \n", portion);

printf("Temp %f   \n", temp);
}