What should I fix to create random calculation in this code? - c

Question

I wanted to fix my code to create random operation here, what should I fix here?
#include <stdio.h>
int main()
{
int x,y,z,a;
char o;
while(1)
{
printf("give your three numbers: ");
scanf("%d %d %d",&x,&y,&z);
printf("(%d*%d-%d) what is the correct among following answers? \n 1. %d\n 2. %d\n 3. %d\n ",
x,y,z,x*y-z,x*y*z,x-y*z);
printf("what is answer? \n: ");
scanf("%d",&a);
if(a == 1)
{
printf("you are right!\n");
}
else
{
printf("you are false!\n\n");
}
getchar();
printf("Would you like to exit programm? (y/n) : ");
scanf("%c",&o);
if (o=='Y' || o=='y')
{
break;
}
else if(o=='N' || o=='n')
{
continue;
}
else
{
printf("Wrong input!!!!");
}
return 0;
}
}
What I mean is I want to try change operation such as * + - randomly when I run code, and also along with this question, the answer should be changed...
thank you!

Answer 1

Your question is mainly focused on shuffling the answers. By studying from couple of sites I have found an solution for this. This is little bit difficult but studying the code few times you can get it
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
void swap(int *a, int *b) {
int temp = *a;
*a = *b;
*b = temp;
}
void randomize(int arr[], int n) {
srand(time(NULL));
int i;
for(i = n-1; i > 0; i--) {
int j = rand() % (i+1);
swap(&arr[i], &arr[j]);
}
}
int main() {
int x,y,z,a;
int i;
int a1, a2, a3;
int arr[] = {1, 2, 3};
int n = sizeof(arr)/ sizeof(arr[0]);
printf("give your three numbers: ");
scanf("%d %d %d",&x,&y,&z);
a1 = x*y-z;
a2 = x*y*z;
a3 = x-y*z;
printf("Before shuffle = %d %d %d\n\n", a1, a2, a3);
char answers[] = {a1, a2, a3};
printf("(%d*%d-%d)what is the correct among following answers?\n", x, y, z);
randomize (arr, n);
for(i=0; i<n; i++) {
int index = arr[i];
printf("%2d - %d\n", i+1, answers[index]);
}
return 0;
}
This is the outputs
First time run
give your three numbers: 2
2
2
Before shuffle = 2 8 -2
(2*2-2)what is the correct among following answers?
1 - 8
2 - 2
3 - -2
Second time run
give your three numbers: 2
2
2
Before shuffle = 2 8 -2
(2*2-2)what is the correct among following answers?
1 - -2
2 - 8
3 - 2
You can try this multiple times. Every time answers will be shuffle. This is the Source I have referred.

Answer 2

Just provide one of examples here. There are many kinds way to implement. In the random operation generation part. I would like to write a random number generator function, which purpose is to generate the given range of random number.
int gen_random(int min, int max)
{
srand( time(NULL) );
return rand() % (max - min + 1) + min;
}
In order to represent four operator (+, -, *, /), The number (let's call the operation number) 1 to 4 is used for represent four operator respectively. The calculation function map the operation number to operation and get the result.
int calculation(int number1, int number2, int op)
{
switch(op)
{
case 1:
return number1 + number2;
case 2:
return number1 - number2;
case 3:
return number1 * number2;
case 4:
return number1 / number2;
}
}
You can use the gen_random and the calculation function above to change operation randomly. The usage of the gen_random and the calculation function is something like:
int op = gen_random(1, 4); // Generate operation randomly
printf("%d\n", op);
printf("%d\n", calculation(x, y, op)); // Pass x, y, and operation number into calculation function to get answer