gnuplot window does not show

Question

I am trying to initialize the gnuplot using C interface, following this example:

#define _CRT_SECURE_NO_DEPRECATE
#include <stdio.h>
void plot(float xValues[], float yValues[], int NUM_POINTS) {
    char* commandsForGnuplot[] = { "set title \"TITLEEEEE\"", "plot 'data.temp'", "fflush(gnuplotPipe)" };
    FILE* temp = fopen("data.temp", "w");
    FILE* gnuplotPipe = _popen("gnuplot -persistent", "w");
    int i;
    for (i = 0; i < NUM_POINTS; i++)
    {
        fprintf(temp, "%lf %lf \n", xValues[i], yValues[i]); //Write the data to a temporary file
    }

    fclose(temp);

    for (i = 0; i < 3; i++)
    {
        fprintf(gnuplotPipe, "%s \n", commandsForGnuplot[i]); //Send commands to gnuplot one by one.
    }
}

void main(){
    float a[] = {0, 1, 2, 5, 8};
    float b[] = {0, 1, 2, 3, 4};
    plot(a, b, 5);
}

For some reason, the plot does not show up. What I should correct?

Edit

Found out that the prompt window shows the following message:

"'gnuplot' is not recognized as an internal or external command, operable program or batch file."

Edit2 Following @theozh added the path to gnuplot.exe and solved the problem

Answer 1

Again my comment as answer, according to the SO "rule": no answers in comments. Otherwise this question would continue to appear unanswered.

Either

• add the path of gnuplot.exe to the Windows environment variable PATH

or

• give the full path of gnuplot.exe in your _popen() command