System pause c ошибка

System pause error

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#include "stdafx.h"
#include <iostream>
#include <Windows.h>

using namespace std;

int main()
{
	char op;
	float num1, num2;

	cout << "Please enter operator (+ , - , * or /) ";
	cin >> op;

	cout << "Enter your two numbers you wish to calculate ";
	cin >> num1;
	cin >> num2;


	switch (op)
	{
	case '+':
		cout << num1 + num2;
		break;

	case '-':
		cout << num1 - num2;
		break;

	case '*':
		cout << num1*num2;
		break;


	case '/':
		cout << num1 / num2;
		break;

	default:
		// if the operator is other than specified it will give an error
		cout << "error, invalid operator please try again. ";
		break;


	}
	return 0;

}

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//#define RELEASE  // First line in the file. Uncomment when testing is finished.

#ifndef RELEASE
#include <conio.h>
#endif

// Program here

#ifndef RELEASE
std::cout << "nnnn Press anykey to continue";
_getch();
#endif

return 0;
}  // End of main 

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case 'q':
case 'Q':
    cont = false;
    break;

Topic archived. No new replies allowed.

1. 03-18-2011

   
   

   #1

   

   
   Registered User
   

   ---

   System Pause Error please help
   

   Code:

   [QUOTE]#include<stdio.h>
   
   int main () {
   int i,j,max_c, max_j;
   int num_shows;
   
       
       FILE * fin;
       fin = fopen("ucfidol.txt","r");
       
       
       fscanf(fin,"%d", &num_shows);
       printf("%dn",num_shows);
       fscanf(fin,"%d",&max_c);
       printf("Number of contestants = %dn", max_c);
       fscanf(fin,"%d",&max_j);
       printf("Number of judges = %dn", max_j);
       
       
   
   //int scores[max_c][max_j];
       //for(i=1;i<=max_c;i++)
           //fscanf(fin,"%d",&max_c);
       //for(j=1;j<=max_j,j++)
           //fscanf(fin,"%d",&max_j);
       
       
       
       
       fclose(fin);
   
   system("PAUSE");

   I am trying to write a code but I keep getting an error with the system pause. I cant seem to figure it out. Even for other codes I have been trying to write.

   ---

2. 03-18-2011

   
   

   #2

   

   
   Registered User
   

   ---

   ---

3. 03-18-2011

   
   

   #3

   

   
   Registered User
   

   ---

   For my class our teacher told us to. This is the only way we learned how to keep the output window open

   ---

4. 03-18-2011

   
   

   #4

   

   
   ATH0
   

   

   ---

   Originally Posted by dubbin240
   

   I am trying to write a code but I keep getting an error with the system pause.

   What error?

   Originally Posted by dubbin240
   

   I cant seem to figure it out.

   I can’t either, because you didn’t tell me what error you got.

   Code:

   #include<stdilb.h>
   #include<stdio.h>
   int main( void )
   {
       system( "pause" );
       printf( "error?n" );
       return 0;
   }

   If you don’t get an error there, then system isn’t your problem. So, what error are you getting?

   Quzah.

   Hope is the first step on the road to disappointment.

   ---

5. 03-18-2011

   
   

   #5

   

   
   Registered User
   

   ---

   I attached a snip of the error

   Attachment 10430

   Code:

   //int scores[max_c][max_j];
       //for(i=1;i<=max_c;i++)
           //fscanf(fin,"%d",&max_c);
       //for(j=1;j<=max_j,j++)
           //fscanf(fin,"%d",&max_j);

   Also Im not too good with arrays. If I want to read in from a file and store the numbers as an array would this be close?

   ---

6. 03-18-2011

   
   

   #6

   

   
   ATH0
   

   

   ---

   See the top two lines of my example? Those are #include directives. They basically say «use the following file». stdlib.h is required for the use of the system function.

   Anytime you see ‘X is undeclared’, it means you are either trying to call a function or variable that it knows nothing about. It doesn’t know anything about it, because it only knows about what is above it in the file. If you haven’t included the appropriate headers at that point, it knows nothing of what the hold.

   edit — for your array edit question

   Arrays are basically like drawers in a cabinet. Each drawer holds whatever type the array is. The drawers of an array of integers each store one integer:

   This would have five drawers, each one holding one int. To put something in one directly:

   Code:

   array[ 2 ] = 12345;

   To put something in with say, scanf, we can do:

   Code:

   scanf( "%d", & array[ 2 ] );

   To put something in each drawer in a loop:

   Code:

   int x = 0;
   for( x = 0; x < 5; x++ )
       scanf( "%d%*c", & array[ x ] );

   Or something to that effect.

   Quzah.

   Last edited by quzah; 03-18-2011 at 05:32 PM.

   Hope is the first step on the road to disappointment.

   ---

7. 03-18-2011

   
   

   #7

   

   
   Banned
   

   ---

   Originally Posted by dubbin240
   

   #include stdlib.h

   ---

8. 03-18-2011

   
   

   #8

   

   
   Registered User
   

   ---

   ok thanks that helped…its weird I have never used the standard library but I have always used system pasue

   ---

9. 03-18-2011

   
   

   #9

   

   
   Banned
   

   ---

   Originally Posted by dubbin240
   

   ok thanks that helped…its weird I have never used the standard library but I have always used system pasue

   Well, for future… everything that’s not a C keyword is either part of the standard library or something you wrote…

   ---

What is a system() function?

system() is a predefined standard C/C++ library function. You can pass input commands such as “date” or “pause” to the system() function which will be executed on the operating system terminal.

Let’s first understand the syntax of the system() function

int system(const char *string);

int: int is the return type of system() function. If the command is executed successfully without any error returns 0 (zero). If any error occurs during function execution then it returns a non-zero value.

system: it is the name of a function.

Const char: You can pass any defined commands as a string to this function.

For example:

system(“date”): It returns and displays the current date from the system.

system(“mkdir  NewDirectory”): It creates a new folder with the name NewDirectory where the program is available

system(“cd”): It returns and displays the current directory path.

What is the use of a system(“pause”) function?

the system (“pause”) function is used to pause the program at any required stage or at the end of the program to check the output of the program on the console terminal.

Some IDE’s wait for the user’s inputs before closing the console window but in some IDE’s, it’s required to add a pause function explicitly so that the console window will wait for the user’s input before closing it.

system pause c++ function is generally used if the user wants to see the output results on the console window. It helps users to debug the program in a better way and users can see output values at different stages of the program.

Required header file to use system(“pause”) function:

To use the system function in your program, you must include the following header file at the beginning of the program.

#include <stdlib.h>

Example of using system(“pause”) function:

#include<iostream>
#include <stdlib.h>
using namespace std;
 
int main()
{
    int storedValues[5] = { 10, 20, 30, 40, 50 };
    
    for (int iCnt=0; iCnt<5; iCnt++) 
    { 
        if ( storedValues[iCnt]== 40) 
	{       
            cout << "Value 40 is available at array position: " << iCnt;
            // pause program
	    system("pause");
        }
    }
}

Disadvantages of the system(“pause”) function:

Dependent on the operating system:

Not all operating system supports system() function. It’s only supported on Windows or DOS operating systems. Linux and other operating systems do not support this function. If you want that your program can run on any operating system then using this function will give you errors on unsupported operating systems.

Resource Heavy function:

This is an operating system-level function. When you call this function, it passes commands to the operating system to pause the execution of the program. To simply pause the program execution, calling an operating system level function is not at all recommended. It’s like calling THOR to fit the fastener in the wall. If we can use any program-level function then that would be great.

Unnecessary header files:

To use the system function, you must include the stdlib.h or cstdlib.h header files at beginning of your program.

If you are not using any other functions from these header files apart from the system function then it’s unnecessary to add an entire header file just for a simple task. It will import all the functions available in these header files. It will unnecessarily increase the size of the dependent libraries.

Impacts program performance:

As it calls the operating system to execute the command and adds the entire header file for a simple function, it definitely impacts program performance. If the performance of a program is critical then you should not use this function. There are cheaper and easy alternate solutions are available to achieve the requirement. Keep reading.

Alternatives of the system(“pause”) function:

There are the following better alternatives available rather than using the system pause c++ function.

Use cin.get() function:

cin.get() is the best alternative for the system(“pause”) function. It will also stop the program execution at the required location. You can use cin.get() function as shown below.

#include<iostream>
using namespace std;
 
int main()
{
    int storedValues[5] = { 10, 20, 30, 40, 50 };
    
    for (int iCnt=0; iCnt<5; iCnt++) 
	{ 
        if ( storedValues[iCnt]== 40) 
		{       
            cout << "Value 40 is available at array position: " << iCnt;
            // pause the program to read output
	    cin.get();
        }
    }
}

cin.get() function stops the program execution and waits for input from the user before executing further. Once the user enters any value then program execution continues. This function can be useful if you want to pass any value to the program during execution.

cin.get() is a program-level function, it will not invoke the operating system to execute the command. system pause c++ is a standard library function hence there is no need to add a separate header file explicitly.

Note:  If you are using the C programing language then use getch() function to pause the program execution.

Add breakpoints in the code:

Adding a breakpoint in the program for debugging is the more preferred and efficient way to evaluate the program execution. If you just want to just debug the output of your program then you can use breakpoints. But this is possible only if you are using any IDE to debug the code. If you are not using any IDE and executing the code from the command line then the first approach is useful.

Also read…

How to call a java jar file from a C++ program using system() function.

Final thoughts:

So here we have understood the details about system function and more importantly about system pause c++ function. We hope this article was useful and you got clear about why we should not use the system(“pause”) function. Please let us know your experience and suggestions in the comment box or you can reach out to us using the contact form. We would be happy to hear from you.