Using MPIR in Qt programs

The last blog introduced how to compile MPIR, and this one talks about how to use it in the program. I mainly use C++ Qt to develop programs, so I only talk about how to apply MPIR in Qt programs.

Here I take the compiled version of mpir_gc as an example, first create a directory: dll_mpir_gc_vc14_win32
and then copy all the required files to this directory, including:

• mpir.h
• mpirxx.h
• mpir_gc_vc14_win32.dll
• mpir_gc_vc14_win32.exp
• mpir_gc_vc14_win32.ilk
• mpir_gc_vc14_win32.lib
• mpir_gc_vc14_win32.pdb

Then create a new text file named: mpir_gc_vc14_win32.pri

Add the following lines to it:

win32: LIBS += -L$$PWD/ -lmpir_gc_vc14_win32
INCLUDEPATH += $$PWD/
DEPENDPATH += $$PWD/

Then add this line to the pro file of our project:

include (./dll_mpir_gc_vc14_win32/mpir_gc_vc14_win32.pri)

The following is a test code, how to compile and run normally shows that everything is set up successfully.

#include <QCoreApplication>
#include <stdio.h>
#include <iostream>
#include <mpir.h>
#include <mpirxx.h>

using std::cout;
using std::endl;
void mpz_test()  //计算 100 的阶乘
{
    mpz_t integ, long_i;
    mpz_init (integ);
    mpz_init (long_i);
    mpz_set_sx(integ, 1);
    for(int i = 2; i<= 100; i++)
    {
        mpz_set_sx(long_i, i);
        mpz_mul(integ, integ, long_i);
    }
    mpz_out_str(stdout, 10, integ);
}

void mpzxx_test() //计算 100 的阶乘
{
    mpz_class sum(1);
    for(int i = 2; i<= 100; i++)
    {
        sum *= i;
    }
    cout << sum << endl;
}

void mpf_test()// 计算 E 到 100 位有效数字
{
    mpf_set_default_prec(500);
    mpf_t sum;
    mpf_init (sum);
    mpf_set_d(sum, 2.0);

    mpf_t long_i;
    mpf_init(long_i);

    mpf_t fact_1;
    mpf_init(fact_1);
    mpf_set_d(fact_1, 1);

    for(int i = 2; i < 100; i ++)
    {
        mpf_set_d(long_i, i);
        mpf_div(fact_1, fact_1, long_i);
        mpf_add(sum, sum, fact_1);
    }
    mpf_out_str (stdout, 10, 100, sum);
}

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    mpzxx_test();
    mpz_test();
    putchar('\n');
    mpf_test();
    return a.exec();
}