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Help with a C program
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Help with a C programPosted:

Almac14
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Status: Offline
Joined: Mar 04, 201212Year Member
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So my struggle is that I have to be able to square root an integer that the user inputs. I know you can use the "sqrt" function from the math.h library but what would be the easier way of using that? My code is as followed:


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

int main(void){
   
    //Define the variables
    int num;
    int less = 0;
    int between = 1;
    int sum = 0;
    int count = 0;
    long avg;
   
   
   
   
    /*Statements and Loops*/
    printf("Please enter random integers, use the number 99999 to stop:");
    scanf("%d", &num);
   
    while(num!= 99999){
        count++;
        sum+= num;

   
    //If statement
    //sqrt function from <math.h>
        //possible to use a for loop?
   
   
   
    //If statement for one number is less than 20
    if(num < 20){
        less = 1;
    }
   
   
    //If statement for all numbers are between 10 and 90
    if(num <= 10 || num >= 90){
        between = 0;
    }
        scanf("%d", &num);
    }
   
    avg = sum/count;
    //Print out the results
    printf("The number of integers is: \t\t%d\n",count);
    printf("The sum of the integers is: \t\t%d\n",sum);
    printf("The average of the integers is: \t%ld\n", avg);
   
    //If, else to print out true or false for a number being less than 20
    if(less == 1){
        printf("At least one number was less than 20: \tTrue\n");
    }else {
        printf("At least one number was less than 20: \tFalse\n");
    }
   
    //If, else to print out true or false for all numbers being between 10 and 90
    if(between == 1){
        printf("All numbers were between 10 and 90: \tTrue\n");
    }else {
        printf("All numbers were between 10 and 90: \tFalse\n");
    }
   
   
    return 0;
}



#2. Posted:
-Deano
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You will want to be able to increase /decrease upper and lower bounds for whatever number you are finding.

This will eliminate numbers either side of the answer and finally reach your actual result.

 
 double SquareRoot(double myValue) {
    double myPrecision =0.000000001; // the result must match this precision before we take it as correct.
    double lowerBound = 0; // start at 0,the lowest possible answer .
    double upperBound = myValue; // start at the value, the highest possible answer.
    double temp = 0; // initialise our working value.

    while (upperBound - lowerBound > myPrecision) { // while we are still finding more precise numbers
            temp = lowerBound + (upperBound - lowerBound) / 2; // finding mid value
            if (temp * temp > myValue) { // if the value is too large, set temp as our new upper bound.
                upperBound = temp;
            } else {
                lowerBound  = temp;
            }   
    }   
    return temp; // once we have a result with enough precision, return that value.
}


PS. This was written with my phone so excuse any obvious mistakes.
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