Thread: 2 questions, (newbie needs help)

Hi, I have just began to learn C. I have familiarized myself with the basic layout of a very small C Program. So far, all I know how to do is write things (eg: Hello World) and enter variables and do basic math ( + - * / ). I was wondering how you do more advanced math like Square Roots and Powers and such. I read on a site something to do with a Header file and some other stuff. Could someone give me the source for a header file and a program that lets u enter a number and then squares the number.

My second question, I already know how to make people type things and have these typed things become variables. However I have only got this to work with numbers! How can u make a word a variable? Once again, the source of a very basic program (such as, type in a name, and then display the name) would be more sufficient than trying to explain it to me.

Thanks - Dave.

The header file for advanced mathematical functions is math.h, surprise

Code:

#include <stdio.h>
#include <math.h>

int main(){
  int num=10;
  int result;
  
  result = sqrt(num);
  printf("%d", result);

  return 0;
}

Making a word a variable requires the use of an array, referred to as a string in this case. There's not a string data type, so you have to use a char array.

Code:

#include <stdio.h>

int main(){
  char array1[50];
  char array2[50];

  printf("Enter your first name: ");
  scanf("%s", array1);
  printf("Your first name is %s\nEnter your whole name: ", array1);
  scanf("%[^\n]", array2);
  printf("Your whole name is %s", array2);
}

The first scanf will allow you to enter a single word, but as soon as it reads in a space it will stop. The second scanf will read until it sees a newline, meaning it will read into the array until it reaches the point where you hit enter.

square root

Code:

#include <math.h>

main()
{
int num;
double answer;

printf("Type in the number: ");
scanf("%d",&num);

answer=sqrt(num);

printf("The sqare root of %d is %f",num,answer);
}

#include <math.h> <-----This is how you add a header file

Code:

main()
{
char name[20];

printf("Please type in your name: ");
gets(name);

printf("Your name is %s",name);
}

Good luck

-Thantos

Thank you all. This solves my problem.