pi - How to get the most decimal precision in C -

i calculating pi in program using indefinite series of terms. when display resulting calculation overall accuracy of pi not want. believe there problems in conversion specifications or primitive types using.

here getting:

pi: 3.141594

here want:

pi: 3.14159265358979323846

here code pi calculation method:

 //global variables   // variables hold number of threads , number of terms   long numofthreads, numofterms;  // variable store pieces of pi being calculated each thread  double pitotal = 0.0;      // use indefinite series of terms calulate pi     void calculatepi(){       // variable store sign of each term       double signofterm = 0.0;       // variable to index of loop variable       long k;  #pragma omp parallel num_threads(numofthreads) \  default(none) reduction(+: pitotal) private(k, signofterm)\  shared(numofterms)       (k = 0; k <= numofterms; k++) {         if (k == 0) {         signofterm = 1.0;         }      // sign of term         else if (k % 2 == 0) {         signofterm = 1.0;         }     // sign of term odd         else if (k % 2 == 1) {         signofterm = -1.0;       }     // computing pi using indefinite series of terms         pitotal += (signofterm) * 4 / (2 * k + 1);         }       }    // print result  void printresult(){       printf("\n" "calulation of pi using %d " "terms: %f",numofterms,pitotal);       }                               

here did solve problem. had change conversion specification %f %.17g. gave me more precision default print value of float.

 // print result   void printresult(){        //returning result 17 places after decimal removing trailing zeros         printf("\n" "the value of pi using %d term(s): %.17g", numofterms, pitotal);        }