C++ Assignment for Intro Engineering - c++

Question

This is the problem my professor wants me to solve with a C++ program...
To design a square timber column in a structure, three formulas must
be satisfied:
column pcture-1.jpg
Buckling load: The maximum load the column can hold for buckling which needs to be greater than the expected load on the column.
Maximum load = (.3 x E x Area) / (Length / Width)2
Compressive stress: The maximum load the column can hold for compression which needs to be greater than the expected load on the
column.
Maximum load = Area x Maximum compressive strength
Slenderness limit: Ratio of Length to Width of the column must be less than or equal to 50
(Length / Width)<= 50
where: E = the modulus of elasticity = 1,700,000 lb/in2
Area = width x width = the cross sectional area in square inches
Maximum compressive strength = 445 lb/in2 for a Douglas Fir tree.
Write a program that uses these three formulas to give an initial
design to a structural engineer. Assume the columns to be used are
square in cross-section and are available in intervals of 2 inches
(i.e. 2 by 2, 4 by 4, 6 by 6 and so on). Have the output look like
the following:
Please enter the expected load on the column in pounds--> 9000
Please enter the length of the column in inches--> 120
... .Testing a beam with Area of 2.0 by 2.0 inches – Failed the tests
... .Testing a beam with Area of 4.0 by 4.0 inches – Failed the tests
... .Testing a beam with Area of 6.0 by 6.0 inches – Passed the 3 required tests
For a load of 9000.0 pounds and a length of 120.0 inches, recommended
square beam has sides of 6.0 inches The timber cost will be $ 216
You must write a function for each of the three tests using call by
value. Your main program will call these three functions in order to
solve the problem. Test your program for the above input and for the
case of 18000 lb load and column length 72 inches. If the price of
the timber is 0.05 $/in3 report the difference between the cost of
the timbers.
This is the program I wrote, but it forms an endless loop; I am not sure how to fix it, and solve the problem my professor wants me to.
#include <iostream>
#include <fstream> // outfile
#include <cmath>
#define E 1700000 // lb/in^3 (E is modulus of elasticity)
#define MCS 445 // lb/in^3 (MCS is maximum compressive strength)
using namespace std;
bool buckling_load();
bool compressive_stress();
bool slenderness_limit();
//1.0 declare variables
float expected_load;
float column_length;
bool tests_passed = false;
float column_width = 2;
int main() {
ofstream outfile;
outfile.open("outfile.txt");
//2.0 get user input
cout << "Please enter the expected load on the column (lbs), and the
column length (in) ->" << endl;
cin >> expected_load >> column_length;
//3.0 test the different widths
while (!tests_passed) {
if (buckling_load() && compressive_stress() && slenderness_limit()){
tests_passed = true;
cout << column_width << " by "<< column_width << " Passed the three required tests";
}
else {
cout << column_width << " by "<< column_width << " Failed the three required tests";
column_width +=2;
}
}
}
//4.0 define functions
bool buckling_load(){
if (expected_load < ((0.3 * E * pow(column_width, 2)) / pow(column_length / column_width, 2))){
return true;
}
else{
return false;
}
}
bool compressive_stress(){
if (expected_load < ((pow(column_width,2)) * MCS)){
return true;
}
else{
return false;
}
}
bool slenderness_limit(){
if(50 <= (column_length/column_width)){
return true;
}
else {
return false;
}
}

Answer 1

This condition
Slenderness limit: Ratio of Length to Width of the column must be less
than or equal to 50
does not correspond to your source:
bool slenderness_limit(){
if(50 <= (column_length/column_width)){
return true;
}
else {
return false;
}
}
The condition should be reversed:
if(50 >= (column_length/column_width))