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// Simple example file for the function parser
// ===========================================
/* Note that the library has to be compiled with
FP_SUPPORT_FLOAT_TYPE, FP_SUPPORT_LONG_DOUBLE_TYPE and
FP_SUPPORT_LONG_INT_TYPE
preprocessor macros defined for this example to work.
Try with these input values with the different floating point parser
types to see the difference in accuracy:
f(x) = x + 1.234567890123456789
min x: 0
max x: 2
step: 1
*/
#include "../fparser.hh"
#include <iostream>
#include <iomanip>
#include <string>
template<typename Parser>
void runExample(const char* valueTypeName)
{
typedef typename Parser::value_type Value_t;
std::cout << "Using " << valueTypeName << " parser." << std::endl;
Parser fparser;
std::string function;
Value_t minx, maxx, step;
fparser.AddConstant("pi", Value_t(3.1415926535897932));
std::cin.ignore();
while(true)
{
std::cout << "f(x) = ";
std::getline(std::cin, function);
if(std::cin.fail()) return;
int res = fparser.Parse(function, "x");
if(res < 0) break;
std::cout << std::string(res+7, ' ') << "^\n"
<< fparser.ErrorMsg() << "\n\n";
}
std::cout << "min x: ";
std::cin >> minx;
std::cout << "max x: ";
std::cin >> maxx;
std::cout << "step: ";
std::cin >> step;
if(std::cin.fail()) return;
Value_t vals[] = { 0 };
for(vals[0] = minx; vals[0] <= maxx; vals[0] += step)
{
std::cout << std::setprecision(20);
std::cout << "f(" << vals[0] << ") = " << fparser.Eval(vals)
<< std::endl;
}
}
int main()
{
int choice = 0;
do
{
std::cout << "1 = double, 2 = float, 3 = long double, 4 = long int: ";
std::cin >> choice;
} while(choice < 1 || choice > 4);
switch(choice)
{
case 1: runExample<FunctionParser>("double"); break;
case 2: runExample<FunctionParser_f>("float"); break;
case 3: runExample<FunctionParser_ld>("long double"); break;
case 4: runExample<FunctionParser_li>("long int"); break;
}
return 0;
}
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