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  1. #include <math.h>
  2. #include <stdio.h>
  3.  
  4. double pnorm_i(int n, double *a, double p) {
  5.   return (n < 0) ? 0.0 : pow(fabs(a[n]), p) + pnorm_i(n - 1, a, p);
  6. }
  7. double pnorm(double p, int n, double *a) {
  8.   return pow(pnorm_i(n - 1, a, p), 1.0 / p);
  9. }
  10.  
  11. int main() {
  12.   double a[] = { 0.5, -0.5 };
  13.   double b[] = { 1.0, 1.0, 1.0, 1.0, 1.0 };
  14.   double c[] = { -1.0, 2.0, 0.0, 3.0 };
  15.   printf("%f\n", pnorm(1.0, sizeof(a) / sizeof(double), a));
  16.   printf("%f\n", pnorm(1.0, sizeof(b) / sizeof(double), b));
  17.   printf("%f\n", pnorm(1.0, sizeof(c) / sizeof(double), c));
  18.   putchar('\n');
  19.   printf("%f\n", pnorm(2.0, sizeof(a) / sizeof(double), a));
  20.   printf("%f\n", pnorm(2.0, sizeof(b) / sizeof(double), b));
  21.   printf("%f\n", pnorm(2.0, sizeof(c) / sizeof(double), c));
  22.   putchar('\n');
  23.   printf("%f\n", pnorm(3.0, sizeof(a) / sizeof(double), a));
  24.   printf("%f\n", pnorm(3.0, sizeof(b) / sizeof(double), b));
  25.   printf("%f\n", pnorm(3.0, sizeof(c) / sizeof(double), c));
  26.   putchar('\n');
  27.   return 0;
  28. }
  29. /* end */
  30.  
Success #stdin #stdout 0.02s 1720KB
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stdin
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Standard input is empty
stdout
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1.000000
5.000000
6.000000

0.707107
2.236068
3.741657

0.629961
1.709976
3.301927
https://ideone.com/A5Dnz
language:
C (gcc 8.3)
created:
12 years ago
visibility:
public

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