Create a function to raise power for an integer - C Function

C examples for Function:Function Definition

Description

Create a function to raise power for an integer

Demo Code

#include <stdio.h>  

double power(double a, int b);  

int main(void) {  
  double x, xpow;  
  int n;  /*from w w  w  . j  a  v  a 2 s . c  om*/
  
  printf("Enter a number and the integer power");  
  printf(" to which\nthe number will be raised. Enter q");  
  printf(" to quit.\n");  
  while (scanf("%lf%d", &x, &n) == 2)  
  {  
       xpow = power(x,n);       /* function call           */  
       printf("%.3g to the power %d is %.5g\n", x, n, xpow);  
       printf("Enter next pair of numbers or q to quit.\n");  
  }  
  printf("Hope you enjoyed this power trip -- bye!\n");  
  return 0;  
}  
  
double power(double a, int b){  
  double pow = 1;  
  int i;  
    
  if (b == 0){  
      if (a == 0)  
          printf("0 to the 0 undefined; using 1 as the value\n");  
      pow = 1.0;  
  }  
  else if (a == 0)  
      pow = 0.0;  
  else if (b > 0)  
      for(i = 1; i <= b; i++)  
       pow *= a;  
  else    /* b < 0 */  
      pow = 1.0 / power(a, - b);  
  return pow;                  /* return the value of pow  */  
}

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