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Hassan Syed1 wrote: When I write whole code in main it works well as soon as put the code in separate files I started getting error.
Which means your compiler/linker options are not correct, but since you failed to share those errors, we can only guess.
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"You can easily judge the character of a man by how he treats those who can do nothing for him." - James D. Miles
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There Errors are explained above your header file declaration does not match your .cpp file. Even in a single file your code for Input_area and Input_trap are both bad and wrong. You will have several warnings which you are just ignoring I take it. Those warnings are real and pointing to a problem you need to fix, which becomes fatal when you turn it to a unit.
You declare this in calculation.h
void input_Area(void);
You have this in your calculation.cpp
float input_Area(void){
LOOK AT THEM .. THEY ARE NOT THE SAME .. the return declare (1st word) differs ... THAT IS YOUR FIRST PROBLEM WITH THE .H FILE
Again we repeat the declaration in the .H file must be EXACTLY the same as the interface actually in the .CPP file.
THERE IS NO EXCEPTION TO THIS RULE .... EVER
So the .H file could be changed to
float input_Area(void);
OR ... the .CPP file could be changed to
void input_Area(void){
I can't work out which definition is correct because you don't actually return anything from input_area. Either could be correct because your code has a big error I can't work out which is right. You have the same problem on float input_Trap. You declared you are returning a float but don't return anything, do you understand what I am saying when I say that????? Even in one big file you will be getting a 2 warnings, something like "function does not return value".
I am struggling why you can't see the problem because you did it correctly in rectangleArea and trapezoidArea, so you know how to return a value when you declare it. So on your code you got right lets mark where you return a float.
float rectangleArea (float width, float length)
{
float Area_Rectange = 0;
Area_Rectange = width * length;
return (Area_Rectange);
}
Now look at Input_area and Input_trap the word return and some value doesn't appear in the code BUT you declared you are returning a float. The compiler and I are both confused with what you are doing. If you declare a float return, then please return one. If you don't want to return a float then change the first word on the declare to void (which matches what you have in the .H file).
On the other issue yes we can move the input stuff to another .CPP and .H file and you generally try and keep units around a theme. However lets just leave it in one first and get that working correctly as you still seem to not grasp the basics and more files just confuses things more.
In vino veritas
modified 13-Jun-16 23:17pm.
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#include <iostream>
using namespace std;
float rectangleArea (float , float); float trapezoidArea (float , float, float);
int main()
{
int choice = 0;
char tryagain = 0;
do
{
cout << "\n\nEnter 1 to calculate the area of Rectangle" << endl;
cout << "Enter 2 to calculate the area of a Trapezoid" << endl;
cout << "\n\nEnter your choice : ";
cin >> choice;
switch(choice)
{
case 1:
{
float width = 0.0, length = 0.0, answer = 0.0;
cout << "Enter the width of rectangle :";
cin >> width;
cout << "Enter the length of rectangle :";
cin >> length;
answer = rectangleArea(width, length); cout << "The area of Rectangle is : " << answer << endl;
break;
}
case 2:
{
float base1 = 0.0, base2 = 0.0, height = 0.0, answer = 0.0;
cout << "Enter base1 of trapezoid : ";
cin >> base1;
cout << "Enter base2 of trapezoid : ";
cin >> base2;
cout << "Enter the height of trapezoid : ";
cin >> height;
answer = trapezoidArea(base1, base2, height); cout << "The area of Trapezoid is : " << answer << endl;
break;
}
default:{
cout << "Neither 1 nor 2 entered." << endl;
}
}
cout << "\n Do you want to do another calculation? : ";
cin >> tryagain;
}while (tryagain == 'Y' || tryagain == 'y');
return 0;
}
float rectangleArea (float width, float length)
{
float Area_Rectange = 0.0;
Area_Rectange = width * length;
return (Area_Rectange);
}
float trapezoidArea (float base1, float base2, float height)
{
float Area_Trapezoid = 0.0;
Area_Trapezoid = height * (base1 + base2)/2;
return (Area_Trapezoid);
}
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How hard is it to put the function signatures in a .h file and the functions themselves in a .c file? Then you just need an additional #include directive, and an adjustment to the make file.
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"You can easily judge the character of a man by how he treats those who can do nothing for him." - James D. Miles
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You are not thinking like a programmer ... at the moment your answers are not needed as you just display them to the console
So one easy option to patch your code in Calculation.CPP is this
void input_Area(void)
{
float width = 0, length = 0, answer = 0;
cout << "Enter the width of rectangle :";
cin >> width;
cout << "Enter the length of rectangle :";
cin >> length;
answer = rectangleArea(width, length);
cout << "The area of Rectangle is : " << answer << endl;
}
That matches your .H header file you don't have to change anything
#ifndef _CALCULATION_H
#define _CALCULATION_H
void input_Func(void);
void input_Area(void);
void input_Trap(void);
float rectangle_Area (float , float);
float trapezoid_Area (float , float, float);
#endif
So you could go and fix input_Trap in the same way I am leaving that as an exercise .. problem fixed.
So there is another alternative which is to return the answer in Calculation.cpp
float input_Area(void)
{
float width = 0, length = 0, answer = 0;
cout << "Enter the width of rectangle :";
cin >> width;
cout << "Enter the length of rectangle :";
cin >> length;
answer = rectangleArea(width, length);
cout << "The area of Rectangle is : " << answer << endl;
return (answer);
}
Now you need to fix the header file Calculation.H
#ifndef _CALCULATION_H
#define _CALCULATION_H
void input_Func(void);
float input_Area(void);
void input_Trap(void);
float rectangle_Area (float , float);
float trapezoid_Area (float , float, float);
#endif
So you could go and fix input_Trap in the same way I am leaving that as an exercise .. problem fixed again.
Look carefully at both answers all that changed is whether you return answer or not. In both cases the .H file matches the .CPP file match.
Either answer is technically correct, there is no way for me to decide because it depends what you intend to do with the unit.
In vino veritas
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Your code is not in a fit state to put in modules .. however I have provided code that does roughly what you want in modules. The code includes error checks on the entry you don't do in any way.
File: Calculation.H
#ifndef _CALCULATION_H
#define _CALCULATION_H
float RectangleArea (float width, float length);
float TrapezoidArea (float base1, float base2, float height);
#endif
File: Calculation.CPP
#include "Calculation.h"
float RectangleArea(float width, float length)
{
float Area_Rectange;
Area_Rectange = width * length;
return (Area_Rectange);
}
float TrapezoidArea(float base1, float base2, float height)
{
float Area_Trapezoid;
Area_Trapezoid = height * (base1 + base2) / 2;
return (Area_Trapezoid);
}
File: Input.H
#ifndef _INPUT_H
#define _INPUT_H
unsigned int MenuInput (char* prompt, unsigned int maxNum);
float GetFloatInput(char* prompt, float min, float max);
#endif
File: Input.CPP
#include <iostream>
#include "input.h"
unsigned int MenuInput(char* prompt, unsigned int maxNum) {
bool validFlag = false;
unsigned int iResult;
do {
printf(prompt);
int err = scanf_s("%u", &iResult);
if ((err == 0) || (iResult > maxNum)) {
printf("Invalid menu choice try again\n");
} else validFlag = true;
scanf_s("%*[^\n]");
} while (validFlag == false);
return (iResult);
}
float GetFloatInput (char* prompt, float min, float max) {
int err;
float fResult;
do {
printf(prompt);
err = scanf_s("%f", &fResult);
if (err == 0) {
printf("Entry is not a float try again\n");
} else {
if (fResult < min) {
printf("Re-enter value below minimum of %f\n", min);
err = 0;
}
if (fResult > max) {
printf("Re-enter value above maximum of %f\n", max);
err = 0;
}
}
scanf_s("%*[^\n]");
} while (err == 0);
return (fResult);
}
File: Source.CPP
#include <iostream>
#include "calculation.h"
#include "input.h"
using namespace std;
float input_area (void) {
float width = GetFloatInput("Enter the width of rectangle :", FLT_EPSILON, FLT_MAX);
float height = GetFloatInput("Enter the length of rectangle :", FLT_EPSILON, FLT_MAX);
return (RectangleArea(width, height));
}
float input_trap(void) {
float base1 = GetFloatInput("Enter base1 of trapezoid : ", FLT_EPSILON, FLT_MAX);
float base2 = GetFloatInput("Enter base2 of trapezoid : ", FLT_EPSILON, FLT_MAX);
float height = GetFloatInput("Enter the height of trapezoid : ", FLT_EPSILON, FLT_MAX);
return (TrapezoidArea(base1, base2, height));
}
int main()
{
bool exitFlag = false;
while (!exitFlag){
printf("\nMain Menu:\n");
printf(" 0) Exit program\n");
printf(" 1) Calculate area of rectangle\n");
printf(" 2) Calculate area of trapezoid\n");
unsigned int choice = MenuInput("Enter your choice : ", 2);
switch (choice) {
case 1:
printf("Area of rectangle = %f\n", input_area());
break;
case 2:
printf("Area of trapezoid = %f\n", input_trap());
break;
default:
exitFlag = true;
}
};
return 0;
}
In vino veritas
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even your code giving error. Have a look at screenshot please. However, Thank you for showing me the correct way to code. I got many point out of it.
Screen Shot of Error = http://i64.tinypic.com/16m0zr4.jpg
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Something funky with GCC compiler but easy to fix include float.h ... its doesn't know what FLT_EPSILON, FLT_MAX are.
These are standard C++ Macro constant definitions so you can just look it up
(float.h) - C++ Reference[^]
So top of Source.CPP becomes
#include <iostream>
#include <float.h>
#include "calculation.h"
#include "input.h"
using namespace std;
In vino veritas
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That one is you ... It is basically telling you it can't find the code for GetFloatInput.
GetFloatInput is defined in Input.H and Input.CPP which are included see here
#include <iostream>
#include "calculation.h"
#include "input.h"
using namespace std;
So we are down to either a typo error or you haven't included Input.CPP into your source files. I assume you cut and paste so unlikely to be a typo so lets try number two.
Did you use the menu system and do .... Project... Add files... to add the new .H and .CPP to your source files to the project? I don't use code blocks but it will be something like that.
Can I ask you to show me the line about the deprecated string function points to .. I am interested to see what GCC is complaining about.
There is possibly another warning you are going to get on the definition of main in Source.CPP can you change it from int main() to
int main(int argc, char**argv)
That is the technically correct definition, not the Microsoft shorthand I used.
In vino veritas
modified 15-Jun-16 12:50pm.
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Excellent. Working fine now however I have to remove scanef_s. that _s was creating problem so i only remove _S and scanef remain as it. Now code working fine. Thank you for ur guidance. Now i got the clear idea how to write the code. I will copy the way you wrote this code. I am not a bad student however I like programming but problem is I think i am unable to think like a programmer. I am trying hard for that but no success yet  I want to excel in this field but sometimes I stuck 
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We all get stuck at times  It is really pleasing to see you are willing to apply yourself to learn. None of us are born able to think like a programmer it is like any profession something you get good at by application of lots of time and effort.
Your long single file code is sort of normal basic student level code, it works in a fashion. You are now seeking to move beyond that and I can only encourage that. All I did was really shorten up your code by making functions with more parameters and putting in error checking for things like typing letters instead of numbers etc. There are improvements you could do by using objects or classes but that is more stuff you are yet to learn.
I looked up the problem with scanf_s it is they have changed security with this, you now need to use "%hu" rather than "%u" as meaning a pointer to an unsigned short. That tells you how many years since I have written code for a console application
So there are two fixes to remove the warning correctly
unsigned short iResult;
int err = scanf_s("%hu", &iResult);
In vino veritas
modified 15-Jun-16 14:35pm.
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You are right. i am completely new and it was my class assignment number 1. I finsihed it and submitted it already but then I came to know professionals never write everything in main that's why i decided to search in this direction. By your improved code I can see a boundery wall is set for wrong inputs. Which i wanted to set in my project as well but was not sure how to set those powerful boundaries as you set. I want to excel in this game of programming, I am not an extera ordinary student but i will keep on trying it day by day
Following are few things I extracted from ur code which I am going to follow for the next time code or will at least try my best to do similar things. Correct me if I observed wrong. I did not follow the following things in my code. If I missed any point then point me that as well.
1) You are using braces by giving one space and starting 1st curly brace in-front of the statements like while and if.
2) All variable you wrote in small letters and to make them more clear u out _ sign to link them.
3) Function name 1st character and then the 2nd meaning name of function is capital.
3) 1 step indentation on each step involving in some kind of computation.
4) You used unsigned when you feel that value are in +ve.
modified 15-Jun-16 17:27pm.
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correct on all counts, you have correctly identified that the standard makes the code much more easily readable and helps you identify errors. I enforce the standards at our company and I therefore never write without using that standard. The standard we use is essentially an extension of C99 or sometimes called ANSI-C standard and is used heavily in the sector I work, which is embedded programming.
Companies in the game market you are looking at tend to use C++ (UNREAL GAME ENGINE etc) or C# (UNITY GAME ENGINE) and there standard may differ slightly as the majority of the code won't be C compliant, and they have other pressures for readability. So generally in large companies you will be expected to write to a standard and there will usually be a process to check code into the active repository.
So while learning coding try and have your own standard but just remember you may have to adapt when you are employed. The company is not going to rewrite an entire repository to your standard even if you could argue it was better. So my standard is not the "absolute best" it's just a standard I would generally have to write to at work.
In vino veritas
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i need to set up glut on my windows machine.
i have glut.h in the include\GL folder , libglut32.a in the lib folder and glut32.dll in the windows\system folder
i compile as follows:
g++ -Wall main.cpp -mwindows libglut32.a -lopengl32 -lglu32
i also have the windows.h , gl/glut.h and gl/gl.h included.
and actually my compiler is tdm-gcc (mingw64)
it gives me lots of errors like:
undefined reference to _glutmainloop...
how do i solve this?
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lol i solved this....
i think glut was too old for my compiler ... so i downloaded freeGLUT and it worked
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GLUT is deprecated on Visual Studio it no longer exists as a standard unit and is recommended not to use, which is what all the errors were about and why you needed to download freeGLUT.
In vino veritas
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yea..
same is the case with codeblocks and bloodshed dev-cpp
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What is the main reason even till day-today there is no boundry condition set for C++. Why not compiler resist that we are pointing something out of the range of our array or we are pointing to a memory location which we cannot points to as it is not in the allowed range of our source code. Why not C++ creator or the IOS committee which build the standard put a check on this thing. There must be some reason of this freedom to point anywhere. I want to know that reason why they are doing like this. If a person like bjarne stroustrup can write such an advance programming language then there must be something special he left this imporant check to move in memory anywhere. If you know about this please share with me. I am curious to know the logic behind it. I asked this question from my teacher but instead of answering me he said this is not a part of my course  I am new student to programming
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If you don't know the answer by ur-self then keep quite.
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You are assuming that there are ordered limits to the set and that boundary has meaning. In a nutshell you seem to be inferring that sets are something like ordered numbers. It's a construction class so lets expand it to the general form, I have a set I called animals in which I inserted an chicken, a pig and a dog.
I now have a Lion is this inside or outside the boundary condition of my animal set? Do you see the problem with your question? What if I told you that my animal set was domestic animals does that change your answer?
Do you get that even if I have a set of numbers in a generic set, those numbers are just place holders for "things" such as animals ... they aren't really numbers like you are using them.
So you may want to review set theory
Set theory - Wikipedia, the free encyclopedia[^]
So the correct answer is if you want boundary conditions on your set because there is some logical order to them, then extend the class yourself. That behaviour is not natural to a generic set class so why would you expect it to be in a generic set class. Nobody has ever asked for that behaviour because it's wrong under set theory, as you are making some very specific sorted or ordered set.
In vino veritas
modified 12-Jun-16 5:18am.
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It sounds an awful lot like you're asking - why does a fast and powerful language like C++ not have one of the performance killers of languages that require less skill to use.
Simply, because with C/C++ you're given the power to shoot yourself in the foot. If you do so, it's your own stupid fault, not that of the language that lets you do it.
If you have an array of a million elements and you wish to access each of them, you're expected to know that you're not trying to access an element before or after your allocated memory. The alternative is to assume you have or will screw-up and to perform 1 million bounds checking operations. No - that's not cool. That's a nice feature for sub-par programmers.
Also, hassan syed1 - it's Bjarne Stroustrup, not bjarne stroustrup. You capitalized your own name but thought his not significant enough to afford him the same respect?
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It does offer boundary condition, just use modern C++ constructs (vector, array, string...) instead of their unsafe C equivalent (pointers, char*...)
If you are using a modern version of Visual Studio, there are additional checks made by the compiler and runtime to check boundary conditions (Security Features in the CRT[^]) and also they offer a set of safer runtime API (all the _s functions like strcpy_s instead of strcpy)
Remember that if the language let you shoot yourself in the foot, there is no excuse try not to by following best practice when coding.
I'd rather be phishing!
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