Input a number with degree - c

Help with problem: I need to write C + + program, which input and displays numeric variables with operators printf and scanf. the values are:
E = 10 ^ 3
F = -450
H = 0,005 * 10 ^ 2
X = -43,562 * 10 ^ (-3)
I = 75600
Y = -0,00036
But I do not understand how I have to enter 10 ^ 3 and other... at the moment my code is ...
#include <stdio.h>
#include <conio.h>
main()
{
int E;
int F;
puts("Введите значения E и F");
scanf("%d,%d", &E,&F);
printf("Значение E=%2d\n",E);
printf("Значение F=%4d\n",F);
puts("-----------------------------");
float H;
float X;
int I;
float y;
puts("Введите значение I");
puts("Введите значение H, X, Y");
getch();
return 0;
}

If I understood your question correctly, the answer is: use scientific notation
10 ^ 3 becomes 1e3,
0.005 * 10 ^ 2 becomes 0.005e-2
and so on

Related

Values inserted to my parameter suddenly vanished after the first expression

I have problems for my function, since after the first expression, the values inserted to my parameters (float x, float y) suddenly becomes 0.
I called this function with main (), the output for c = x/y works as expected. But for d = x - (y * c), it gives me an output of 0, I check where the problem is and it appears to be because of x and y since they both have 0 values for some reason
I have not finished my function for greatest common divisor, since I'm still stuck at this problem
'''
int gcd (float x, float y)
{
int c = x / y;
printf ("This's your quotient: %d\n", c);
int d = x - ( y * c ); // d = 0 since y, x = 0
printf ("This's your remainder: %d\n", d);
printf ("c %d\n",c); // works normally
printf ("y %f\n",y); // y = 0
printf ("x: %f\n",x); // x = 0
}
Here is example code that fixes the issues I noticed and changing the signature to separate calculations from output:
#include <stdio.h>
void quotient_reminder(unsigned x, unsigned y, unsigned *q, unsigned *r) {
if(y == 0) return;
*q = x / y;
*r = x - (y * *q); // d = 0 since y, x = 0
}
int main() {
unsigned q, r;
quotient_reminder(25.0, 7.1, &q, &r);
printf ("This's your quotient: %u\n", q);
printf ("This's your remainder: %u\n", r);
}
and it will return:
This's your quotient: 3
This's your remainder: 4

How to use exp and sqrt properties correctly

-use double precision
-use sqrt() and exponential function exp()
-use * to compute the square
-do not use pow()
I am getting values they are just not anything as to what I expected. I tried making them all signed but it didn't change anything and I've tried printing out with 12 decimal places and nothing seems to be working.I have linked the math library and defined it as well.
double normal(double x, double sigma, double mu)
{
double func = 1.0/(sigma * sqrt(2.0*M_PI));
double raise = 1.0/2.0*((x-mu)/sigma);
double func1 = func * exp(raise);
double comp_func = (func1 * func1);
return comp_func;
}
int main(void)
{
// create two constant variables for μ and σ
const double sigma, mu;
//create a variable for x - only dynamic variable in equation
unsigned int x;
//create a variable for N values of x to use for loop
int no_x;
//scaniing value into mu
printf("Enter mean u: ");
scanf("%lf", &mu);
//scanning value into sigma
printf("Enter standard deviation: ");
scanf("%lf", &sigma);
//if sigma = 0 then exit
if(sigma == 0)
{
printf("error you entered: 0");
exit(0);
}
//storing number of x values in no_x
printf("Number of x values: ");
scanf("%d", &no_x);
//the for loop where i am calling function normal N times
for(int i = 1; i <= no_x; i++)
{
//printing i for the counter in prompted x values
printf("x value %d : ", i);
// scanning in x
scanf("%lf", &x);
x = normal(x,sigma,mu);
printf("f(x) = : %lf.12", x);
printf("\n");
}
return 0;
}
C:>.\a.exe
Enter mean u: 3.489
Enter std dev s: 1.203
Number of x values: 3
x value 1: 3.4
f(X) = 0.330716549275
x value 2: -3.4
f(X) = 0.000000025104
x value 3: 4
f(X) = 0.303015189801
But this is what I am receiving
C:\Csource>a.exe
Enter mean u: 3.489
Enter standard deviation: 1.203
Number of x values: 3
x value 1 : 3.4
f(x) = : 15086080.000000
x value 2 : -3.4
f(x) = : 15086080.000000
x value 3 : 4
f(x) = : 1610612736.000000
Insert these lines:
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
Change:
const double sigma, mu;
to:
double sigma, mu;
Change:
unsigned int x;
to:
double x;
Replace the definition of the normal function with:
double normal(double x, double sigma, double mu)
{
double func = 1.0/(sigma * sqrt(2.0*M_PI));
double t = (x-mu)/sigma;
return func * exp(-t*t/2);
}
#define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#ifndef M_PI
#define M_PI (3.14159265358979323846)
#endif
#include<math.h>
#include<stdio.h>
#include <stdlib.h>
double normal(double x, double sigma, double mu)
{
double func = 1.0/(sigma * sqrt(2.0*M_PI));
double t = (x-mu)/sigma;
return func * exp((-0.5*t)* t);
}
I Finally got this code above working after tweaking with it literally all day lol, C math can be rather tricky, thank you for the help above as well.

Rotation program in C

I'm basically trying to make a math rotation program in C. But the output is always wrong. P(x,y) is rotated about Q(r,s); clockwise (direction=1) or anticlockwise (direction=0). The a,b,c are angles in triple ,I guess question meant c is in hundred's then b is in ten's and a is unit's.
Input:
0
7 3
0 1 1
0 0
Output: -3 7
Whereas I'm getting -5 5.
Thanks for your time if you help me.
Original question link: https://www.codechef.com/problems/DSPC305
i found another question by the same uploader which uses TRIPLE too. He further added a note :Triple is defined by a,b,c where a is base, b is height and c is hypotenuse of a triangle. Each triple corresponds to an angle given by cosA= a/c
#include<stdio.h>
#include<math.h>
int main() {
int x,y,a,b,direction,c,r,s,xnew,ynew;
scanf("%i", &direction);
scanf("%i %i", &x, &y);
scanf("%i %i %i" , &a, &b, &c);
scanf("%i %i", &r, &s);
float PI = 3.1415926535897932384626;
float theta = ((c*100+b*10+a)*PI)/180;
if (direction==1)
{
xnew= (x-r) * cos(theta) + (y-s) * sin(theta);
ynew= -(x-r) * sin(theta) + (y-s) * cos(theta);
printf("%i %i", xnew+r, ynew+s);
}
if (direction==0)
{
xnew =( (x-r) * ((cos(theta))) - (y-s) * sin(theta));
ynew =( (x-r) * ((sin(theta))) + (y-s) * cos(theta));
printf("%i %i", (xnew+r), (ynew+s));
}
return 0;
}
This
float theta = ((c*100+b*10+a)*PI)/180;
has nothing to do with the definition of a triple.
You can use this code:
#include<stdio.h>
#include<math.h>
int main()
{
double xp,yp,xq,yq,a,b,c;
double t,xn,yn;
int z;
scanf("%d",&z);
scanf("%lf%lf",&xp,&yp);
scanf("%lf%lf%lf",&a,&b,&c);
scanf("%lf%lf",&xq,&yq);
t=asin(b/c);
if(z==0)
{
xn=xp*cos(t)-yp*sin(t)-xq*cos(t)+yq*sin(t)+xq;
yn=xp*sin(t)+yp*cos(t)-xq*sin(t)-yq*cos(t)+yq;
}
else
{
xn=xp*cos(t)+yp*sin(t)-xq*cos(t)-yq*sin(t)+xq;
yn=-xp*sin(t)+yp*cos(t)+xq*sin(t)-yq*cos(t)+yq;
}
printf("%0.lf %0.lf",xn,yn);
return 0;
}
This code gave correct output for both of the test cases provided in the question.
Do tell if it worked :)

What's the fastest method to trim a number between -PI and +PI in C?

Say I have a high floating point number... 1345.23
I want to reduce it by 2*PI until it stays between -PI and +PI so I'd do:
#define PI 3.14159265358f
#define TWO_PI 6.28318530718f
float a = 1345.23f;
while (a > PI) a -= TWO_PI;
Do you know a fastest method?
With this code you will enter in the loop just 1 time (you can delate it adding just a more a -= TWO_PI
#include <stdio.h>
#define PI 3.14159265358f
#define TWO_PI 6.28318530718f
int main(void) {
float a = 1345.23f;
float b = 1345.23 - PI;
int c = b/TWO_PI;
a -= c*TWO_PI;
int i = 0;
while (a > PI){
a -= TWO_PI;
printf("%d",i++);
}
printf("\na : %f",a);
}
OUTPUT:
0
a : 0.628314
While your code will do the cicle :
214 times
BETTER CODE:
#include <stdio.h>
#define PI 3.14159265358f
#define TWO_PI 6.28318530718f
#define INV_TWO_PI 0.15915494309189533
int main(void) {
double a = 1345.23;
if(a > PI){
double b = a - PI; // you get the distance between a and PI
// int c = b/TWO_PI; // you get the integer part
int c = b * INV_TWO_PI; // the same as above using multiplication
a -= (c+1)*TWO_PI; // you just subtract c+1 times TWO_PI
// c+1 cause you want come in the range [-PI,PI]
}
}
Not the fastest, but the shortest code:
y = asin(sin(a));
Assuming that your code has to do with phase wrapping in radians, so that values between PI and TWO_PI can map between -PI and 0.0 a simple and fast solution would be:
double a = 1345.23;
double b = TWO_PI;
double c = (fmod(a,b) > PI ? fmod(a,b) - b : fmod(a,b));
After accept answer
To quickly reduce between -PI and PI, simply use remquof();
#include <math.h>
#include <stdio.h>
float reduce_radian(float x) {
static const float pi2 = 6.283185307179586476925286766559f;
int n;
return remquof(x, pi2, &n);
}
int main(void) {
printf("x % .10e\ty % .10e\n", 1e-30, reduce_radian(1e-30));
for (float x = 0.0f; x <= 4.0f; x += 1.0f) {
printf("x % .10f\ty % .10f\n", -x, reduce_radian(-x));
printf("x % .10f\ty % .10f\n", x, reduce_radian(x));
}
}
Output
x 1.0000000000e-30 y 1.0000000032e-30
x -0.0000000000 y -0.0000000000
x 0.0000000000 y 0.0000000000
x -1.0000000000 y -1.0000000000
x 1.0000000000 y 1.0000000000
x -2.0000000000 y -2.0000000000
x 2.0000000000 y 2.0000000000
x -3.0000000000 y -3.0000000000
x 3.0000000000 y 3.0000000000
x -4.0000000000 y 2.2831854820
x 4.0000000000 y -2.2831854820
To understand why this is not the best precise answer, is a deep subject.
See K.C. Ng's "ARGUMENT REDUCTION FOR HUGE ARGUMENTS: Good to the Last Bit"

Conveying a formula in C (% is)

So I have to make this formula "y = y / (3/17) - z + x / (a % 2) + PI" in C
I am having a problem with (a%2) as it is returning odd values. ie 1%2 = 0.000001
int assignment7()
{
#define PI 3.14
int a=0,amod2;
double Ny=0,y=0,z=0,x=0;
printf("Enter values for x,y,z and a: ");
scanf("%d%lf%lf%lf",&a,&y,&z,&x);
//printf("%d,%lf,%lf,%lf\n",a,y,z,x);
//amod2=1%2;
//printf("%lf",amod2);
Ny=y/(double)(3/17) - z+x / amod2 + PI;
printf("%lf\n",Ny);
When you say:
printf("%lf",amod2);
the compiler expects amod2 to be a "long float" (aka a double), but you defined it as:
int amod2;
Also your prompt says "x,y,z and a" but you read in the order "a,y,z,x":
printf("Enter values for x,y,z and a: ");
scanf("%d%lf%lf%lf",&a,&y,&z,&x);
that's awkward at best.
EDIT: cleaned up a bit and made some assumptions about order of operations:
#include <stdio.h>
#define PI 3.14
#define DIVSOR (3.0/17.0)
int assignment7 ( void );
int assignment7 ( void ) {
double x = 0.0;
double y = 0.0;
double z = 0.0;
int a = 0;
int amod2;
double Ny;
printf("Enter values for x,y,z and a: ");
scanf("%lf%lf%lf%d",&x,&y,&z,&a);
amod2 = a % 2;
Ny = (y / DIVSOR) - z + (x / amod2) + PI;
printf("%lf\n", Ny);
return 0;
}
int main ( void ) { return assignment7(); }
You don't say what inputs you are giving it, (a test case with inputs and the expected results would be super helpful), but I can point out that x / (a % 2) is going to be infinity when a is 2 or 4 or 6 or ...

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