Question

can someone tell me what's wrong with this? I'll highlight the part I need help with

Answer 1

////Calculator

#include <stdio.h>
#include <stdlib.h>
#include <windows.h>

long factorial(int value);
int permutation(int n, int r);
int combination(int n, int r);
int power(int base, int exponent);
void loading();
float binomdist(int n, int r, float p, float q);

main()
{
int menuChoice;
int fctrl;
int n, r;
int base, exp, pow;
char yn[2];
float p, q;

while (1){
system("cls");
printf("\n Main Menu");
printf("\n =========\n\n");
printf(" <1> Factorial\n");
printf("\n <2> Permutation\n");
printf("\n <3> Combination\n");
printf("\n <4> Power\n");
printf("\n <5> Binomial Distribution\n");
printf("\n\n Enter a number from 1 to 4 > ");
scanf("%d", &menuChoice);
loading();
system("cls");

if (menuChoice == 1)
{
printf("\n What number would you like to take the factorial? ");
scanf("%d", &fctrl);
printf("\n\n Computing...\n");
Sleep(1000);
printf("\n\n %d! is %d\n\n\n ", fctrl, factorial(fctrl));
system("pause");
}
else if (menuChoice == 2)
{
printf("\n Enter the value of n > ");
scanf("%d", &n);
printf("\n Enter the value of r > ");
scanf("%d", &r);
printf("\n\n Computing...\n");
Sleep(1000);
printf("\n\n %dP%d is %d\n\n\n ", n, r, permutation(n,r));
system("pause");
}
else if (menuChoice == 3)
{
printf("\n Enter the value of n > ");
scanf("%d", &n);
printf("\n Enter the value of r > ");
scanf("%d", &r);
printf("\n\n Computing...\n");
Sleep(1000);
printf("\n\n %dC%d is %d\n\n\n ", n, r, combination(n,r));
system("pause");
}
else if (menuChoice == 4)
{
printf("\n Enter base > ");
scanf("%d", &base);
printf("\n Enter exponent > ");
scanf("%d", &exp);
pow = power(base,exp);
printf("\n\n Computing...\n");
Sleep(1000);
printf("\n\n %d raised to %d is equal to %d\n\n\n ", base, exp, pow);
system("pause");
}
else if (menuChoice == 5)
{
printf("\n Enter the number of trials > ");
scanf("%d", &n);
printf("\n Enter the number of successes > ");
scanf("%d", &r);
printf("\n Enter the probability of successs in one trial > ");
scanf("%f", &p);
q = 1 - p;
printf("\n\n Computing...\n");
Sleep(1000);
printf("\n\n The binomial probability is %f\n\n\n ", binomdist(n, r, p, q));
system("pause");
}
else
continue;

loading();

while (1)
{
system("cls");
printf("\n Try again? <Y/N> ");
scanf("%s", yn);

if (yn[0] == 'y' || yn[0] == 'Y')
break;
else if (yn[0] == 'n' || yn[0] == 'N')
return 0;
else
continue;
}
loading();
}
}

long factorial(int value)
{
long fac;
int cntr;
fac = 1;
for (cntr = 1; cntr <= value; cntr++)
fac = fac*cntr;
return fac;
}

int permutation(int n, int r)
{
int perm;
perm = (factorial(n))/(factorial(n-r));
return perm;
}

int combination(int n, int r)
{
int comb;
comb = (permutation(n,r))/(factorial(r));
return comb;
}

int power(int base, int exponent)
{
int pow, cntr;
pow = base;
for (cntr = 1; cntr < exponent; cntr++)
pow = pow*base;
return pow;
}

void loading()
{
int cntr, ctr;
for (cntr = 0; cntr < 3; cntr++)
{
system("cls");
printf("\n\n\n\n\n\n\n\n\n\t\t\t\t Loading");
for (ctr = 0; ctr < 3; ctr++)
{
printf(".");
Sleep(300);
}
}
}
```
float binomdist(int n, int r, float p, float q)
{
float bd;
int a, b, c;
float d;
a = combination(n,r);
b = power(p, r);
c = n - r;
d = power(q,c);
bd = a * b * d;
return bd;
}
```

Answer 2

it looks fine - the binomial P(n,r,p) is C(n,r)*pow(p,r)*pow(q,n-r), with q = 1-p.
Ah - your power(p,r) returns an int value - power(p,r) must be a float - in fact, power(a,b) takes int arguments - p,q are floats...

Answer 3

hmm so what should i do?

Answer 4

float power(float base, int exponent){
float pow = base;
for (int i = 1; i < exponent; i++) {
pow = base * pow;
}
return pow;
}
should work...