Save data for gnuplot

#include<stdio.h>

int main(int argc,char** argv){

    //Open File
    FILE* f = fopen("plotdata","w");
    if(!f){return -1;}

    //Write Graph1
    for(double x=0;x<=10;x+=1){
        double y = x*x;
        fprintf(f,"%lf %lf \n",x,y);
    }

    //Separate data-block by 2 new lines
    fprintf(f,"\n\n");

    //Write Graph2
    for(double x=0;x<=10;x+=1){
        double y = x*x*x;
        fprintf(f,"%lf %lf \n",x,y);
    }

    //Close File
    fclose(f);
}