How to quit loop when requirement is met in C - c

I have made a while loop and it works partly. I want the code to stop when the values entered are under the parameter, but it keeps going regardless of the output. Here is my code:
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <math.h>
#include <time.h>
int main()
{
// defining variables until "till here" comment
int i;
int rollDice;
int firInp;
int secInp;
srand (time(NULL)); // seeding rand so that we get different values every time
// till here
while(rollDice > 0)
{
printf("Enter the amount of faces you want your dice to have (MAX=24, MIN=1): "); // prints the message
scanf("%d", &firInp); // user input stored into firInp
printf("Enter the amount of throws you want(MAX=499, MIN=1): "); // this message is printed after the users first input
scanf("%d", &secInp); // user input stored into secInp
if (((firInp < 25)&&(firInp > 1))&&((secInp < 500)&&(secInp > 1))){ // if statement to check parameters
for(i = 0; i < secInp; i++){
rollDice = (rand()%firInp) + 1;
printf("%d \n", rollDice);
}
}
else{
printf("Sorry, these numbers don't meet the parameters\nPlease enter a number in the right parameters.\n");
}
}
return 0;
}
I'm new to C btw.
edit: I want the loop to continue if the user input is more than 24, 499 respectively.

What you're doing is wrong. Variable rollDice is for storing the values of the outcomes rather than doing a condition check. It will have random values and since the values on the dice can't be negative or zero it may not exit the while loop. I don't know what will rand() will produce so I'm just assuming.
The range for rand() is [0,RAND_MAX), including zero and excluding RAND_MAX. But because of this expression (rand()%firInp) + 1 , you're adding one to it. So it will never become Zero.
You can use a flag variable and set it to 1. When the if conditions are met, you can set the flag to 0. It will exit the while loop.
Corrected code :-
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <math.h>
#include <time.h>
int main()
{
// defining variables until "till here" comment
int i;
int rollDice;
int firInp;
int secInp;
int flag = 1;
srand (time(NULL)); // seeding rand so that we get different values every time
// till here
while(flag)
{
printf("Enter the amount of faces you want your dice to have (MAX=24, MIN=1): "); // prints the message
scanf("%d", &firInp); // user input stored into firInp
printf("Enter the amount of throws you want(MAX=499, MIN=1): "); // this message is printed after the users first input
scanf("%d", &secInp); // user input stored into secInp
if (((firInp < 25)&&(firInp > 1))&&((secInp < 500)&&(secInp > 1))){ // if statement to check parameters
for(i = 0; i < secInp; i++){
rollDice = ((rand() + 1)%firInp);
printf("%d \n", rollDice);
}
flag = 0;
}
else{
printf("Sorry, these numbers don't meet the parameters\nPlease enter a number in the right parameters.\n");
}
}
return 0;
}
EDIT :-
Also, division with 0 is undefined. rand() can attain value 0. You should add 1 to rand() rather than adding to whole modulus. It can create an error if the rand() will give 0 as an output.

Related

Can you Help me correct this simple c program's little mistake?

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
int main()
{
int num, rnum, times = 1;
srand(4383);
rnum=rand() % 300 + 1;
while(times <=8)
{
printf("Guess the numper random number between 1-300: ");
scanf("%d", &num);
if (num<rnum)
{
printf("The random number is biger\n");
}
if (num>rnum)
{
printf("The magic number is smaller\n");
}
if (num == rnum)
{
printf("RIGHT!");
break;
}
times++;
}
printf("FAILURE!");
return 0;
}
The point of the task is to make a program for a user to type and try to guess a numper from 1–300 with 8 attempts. If you find the number it shows RIGHT! and if not it guides you by telling that the number is biger/smaller. If you fail in your 8 atemts then it shows failure. The problem is that it shows failure when you fail to guess in your 8 atempts but when you find the number it prints both RIGHT & FAILURE. What should i correct for the program to print failure only when you cant’t find the number within your 8 tries?
My 2 cents, path of least resistance is to simply return rather than break when the user guesses correctly:
if (num == rnum)
{
printf("RIGHT!");
return 0; // program exits here, no FAILURE print
}
You should also seed the rand function with a changing number, like time. With a constant, you'll find your number to guess is the same every time.
srand(time(NULL)); // randomize seed
You should check if they exceeding the 8 try limit before executing the print statement:
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
int main()
{
int num, rnum, times = 1;
srand(4383);
rnum=rand() % 300 + 1;
while(times <=8)
{
printf("Guess the numper random number between 1-300: ");
scanf("%d", &num);
if (num<rnum)
{
printf("The random number is biger\n");
}
if (num>rnum)
{
printf("The magic number is smaller\n");
}
if (num == rnum)
{
printf("RIGHT!");
break;
}
times++;
}
if (times > 8)
{
printf("FAILURE!");
}
return 0;
}
I think you should write return 0; instead of break; after printing RIGHT. because if you guess the rnum it will print RIGHT and breaks out and after that it will print FAILURE too but if you write return 0; it will end the program.
When you break; out after having printed RIGHT! you end up where you print FAILURE! so you need to check this somehow.
Here's my take on it:
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
int main() {
int num = 0, rnum;
// This game will get boring with a static seed.
// I'm assuming you use this seed for testing only.
srand(4383);
rnum = rand() % 300 + 1;
for(int times = 0; times < 8; ++times) { // simpler loop
printf("Guess the random number between 1-300: ");
// if the user fails to enter a number - make it print FAILURE
if(scanf("%d", &num) != 1) break;
if(num < rnum)
puts("The random number is bigger");
else if(num > rnum) // added "else"
puts("The magic number is smaller");
else
break; // neither less nor greater than rnum so it must be correct
}
if(num == rnum) // added check
printf("RIGHT!\n");
else
printf("FAILURE!\n");
}

How to insert output into an array in c

My code:
// DICE ROLL PROGRAM
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <time.h>
int main()
{
// defining variables until "till here" comment
int i;
int rollDice;
int firInp;
int secInp;
int flag = 1; // flag variable set to 1 which will later be set to zero
srand (time(NULL)); // seeding rand so that we get different values every time
// till here
while(flag) // while loop runs as long as flag variable has a value
{
printf("Enter the amount of faces you want your dice to have (MAX=24, MIN=2): "); // prints the message
scanf("%d", &firInp); // user input stored into firInp
printf("Enter the amount of throws you want(MAX=499, MIN=2): "); // this message is printed after the users first input
scanf("%d", &secInp); // user input stored into secInp
if (((firInp < 25)&&(firInp > 1))&&((secInp < 500)&&(secInp > 1))){ // if statement to check parameters met
for(i = 0; i < secInp; i++){
rollDice = (rand()%firInp) + 1; // added 1 to rand because if the value is ever zero, you will get an error
printf("%d \n", rollDice);
}
flag = 0; // now the flag variable is set to zero, exiting the while loop
}
else{
printf("Sorry, these numbers don't meet the parameters\nPlease enter a number in the right parameters.\n");
}
}
return 0;
}
I want to input the values I obtain from "rollDice" into an array.
for example: If the user enters firInp and secInp as 6, and they get the following values:
1
2
2
3
1
6
I want these numbers to be stored in an array like so:
arrayA = [1,2,2,3,1,6]
Well it really depends on the particular codebase - my example uses stack frame allocation but it could easily be done using the malloc/calloc method suggested in the comments
(The following is pseudocode, you wil need to integrate it into your application)
int main() {
int dice_rolls[6];
for(int i = 0; i < 6 i++) {
roll = rollTheDice(); // In your program you have your own method for getting this number - the point still stands
dice_rolls[i] = roll;
}
}

How to enter an output into an array in c

My Code so far:
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <math.h>
#include <time.h>
int main()
{
int i;
int rollDice;
int firInp;
int secInp;
printf("Enter the amount of faces you want your dice to have (MAX=24, MIN=1): ");
scanf("%d", &firInp);
printf("Enter the amount of throws you want(MAX=499, MIN=1): ");
scanf("%d", &secInp);
srand ( time(NULL) );
if (((firInp < 25)&&(firInp > 1))&&((secInp < 500)&&(secInp > 1))){
for(i = 0; i < secInp; i++){
rollDice = (rand()%firInp) + 1;
printf("%d \n", rollDice);
}
}
else{
printf("Sorry, these numbers don't meet the parameters. Please enter a number in the right parameters.");
}
return 0;
}
I want to have percentages in my code. I think the way to do that is to first enter the output of my code into an array. If there's another way please feel free to let me know.
edit: I want the output to be something like this:
1 3 4 4 4 5
occurrence of 1: 16.6 percent
occurrence of 3: ..and so on
Instead of entering the output of the random function in an array you could just use that array as a counter, and incrementing the array at position rollDice every time a number appears. Than you could easily extract the percentage by summing all the elements of the array and by dividing each element by that sum.
You can create an array of integers, with size equals to the numbers of possible values your dice can output. Then you use it as a counter for the number of occurences you get, the index of the array will represent that output value (you can use rollDice-1 since 0 isn't a possible output of the dice), and the value at the index will be the number of occurences.
After you finish rolling the dice you just have to print the percentage like this:
for (int i=0;i<firInp;i++) { // firInp: n_faces = n_possible_values
printf("Occurrence of %d: %.1f percent\n", i+1, ((float)array[i]*100)/(float)secInp);
}

Random number generator game in C

I have started C recently and am having trouble make the computer think of a random number.
This is the code so far. I need help!
#include <stdio.h>
#include <stdlib.h>
int main ()
{
time_t t;
int userin;
printf("Guess a number from 1 to 10\n");
scanf("%d", userin);
int r = rand() % 11;
if (r == userin)
{
printf ("you are right");
}
else
{
printf("Try again");
}
return 0;
}
Thx a lot guys it worked out!!!!
In your code, r will be a random number from 0 to 10. For a random number between 1 and 10, do this:
int r = rand() % 10 + 1;
Also, you should call
srand(time(NULL));
at the beginning of main to seed the random number generator. If you don't seed the generator, it always generates the same sequence.
There is issue in your scanf statement as well.
You should use
scanf("%d", &userin);
instead of
scanf("%d", userin); /* wrong - you need to use &userin */
scanf needs the address of variables at which it will store the value. For a variable, this is given by the prefexing the variable with &, as in &userin.
There are few issues in your code.
not reading into the address & of your variable using scanf
not considering "legitimate" values of input, result of rand()%11 can also be 0
not checking against "illegal" input values, which can "alias" the result.
not properly initializing seed of the pseudo-random rand() function, so it always returns the same result.
Using printf for debugging your code, as in the following example, based on your code can help a lot:
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define DEBG 1
int main (void)
{
time_t t;
int userin;
printf("Guess a number from 1 to 10\n");
if(scanf("%d", &userin) != 1){ // read into the variable's address
printf("Conversion failure or EOF\n");
return 1;
}
if(userin < 1 || userin > 10){ // check against "illegal" input
printf("Offscale, try again\n");
return 1;
}
srand(time(NULL)); // initialize the seed value
int r = 1 + rand() % 10; // revise the formula
if (DEBG) printf("%d\t%d\t", r, userin); //debug print
if (r==userin){
printf ("you are right\n");
}else{
printf("Try again\n");
}
return 0;
}
Please, also consult this SO post.
Problems :
scanf("%d", userin); //you are sending variable
This is not right as you need to send address of the variable as argument to the scanf() not the variable
so instead change it to :
scanf("%d", &userin); //ypu need to send the address instead
and rand()%11 would produce any number from 0 to 10 but not from 1 to 10
as other answer suggests, use :
(rand()%10)+1 //to produce number from 1 to 10
Solution :
And also include time.h function to use srand(time(NULL));
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
int main(void)
{
srand(time(NULL));
int userin;
printf("Guess a number from 1 to 10\n");
scanf("%d", &userin);
int r = (rand() % 10)+1;
if (r==userin)
{
printf ("you are right");
}
else
{
printf("Try again");
}
return 0;
}
Why use srand(time(NULL)) ?
rand() isn't random at all, it's just a function which produces a sequence of numbers which are superficially random and repeat themselves over a period.
The only thing you can change is the seed, which changes your start position in the sequence.
and, srand(time(NULL)) is used for this very reason
This should work
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
int main ()
{
int userIn = 0; //I like to initialize
printf("Guess a number from 1 to 10\n");
scanf("%d", &userIn);
srand(time(NULL)); //seed your randum number with # of seconds since the Linux Epoch
int r = (rand()%10)+1; //rand%11 gives values 0-10 not 1-10. rand%10 gives 0-9, +1 makes sure it's 1-10
if (r == userIn)
{
printf ("you are right\n");
}
else
{
printf("Try again\n");
}
return 0;
}
Edit: You may want to implement code to verify that the user input is in fact an integer.

how can I increment in this code

Write a program that displays a new random permutation of the integers 0 to 9 at the request of its user. For example, the program’s output could be as follows:
Your program should prints how many 7 was printed when user type no.
My code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
int main()
{
int i , total , r;
char ans;
srand(time(NULL));
do{
for( i=0 ; i < 10 ; i++)
{
r= (rand()%(9-1+1)) + 1;
printf ("%d ",r);
}
total =0;
if (r==7) // Here how can I correct this so total will increase every time
{ // there is a 7 in the string
total++;
}
printf("\nAnother permutation: y/n?\n");
scanf(" %c",&ans);
if (ans != 'y')
{
printf("Bye!\n");
printf("The number of 7's is: %d", total);
}
}while(ans=='y');
return 1;
}
I have a problem with my code. How can I increment the 7's shown in this program after != 'y'.
Set total=0 before entering into the do-while loop, to get the correct total.

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