CODEWITHSUNDEEP
c
user12085035
user12085035

Reputation:

Simple C program won't run. Crashes in CMD

I'm new to programming in C and I'm trying to build and execute my first programs. My first program was Hello, World printed in the CMD like many of you. It worked great. Now it's onto bigger and better projects though and I'm having a weird issue.

I'm trying to make a basic addition calculator using standard IO operations (scanf and printf) and it won't function properly.

My program asks for 2 numbers to be input by the user and it will then display the output of said calculation. The program executes flawlessly until the scanf expression comes into play. After I input my 2 numbers to be added the CMD prompt just closes without warning and never spits out an answer or the text I have to be displayed afterward.

I tried multiple solutions to fix this problem including copying and pasting the source code directly from the website I was learning from, even their perfect code nets the same outcome..just a crash before an output is displayed. I'm posting today because I'm wondering where my issue is coming from because I'm just not sure why this program won't execute as it's supposed to. Thanks in advance and heres the code I'm working with:

#include <stdio.h>

int main()

{
   int a, b, c;

   printf("Enter two numbers to add\n");
   scanf("%d%d", &a, &b);

   c = a + b;

   printf("Sum of the numbers = %d\n", c);

   return 0;
}

Upvotes: 3

Views: 581

Answers (2)

Imran Rana
Imran Rana

Reputation: 11899

Once console application returns from main method, the associated console window closes automatically. I assume you are using Windows OS. In that case add a system("pause"); before your return 0; statement. For platform independent solution you can just show a prompt to user and wait for a key press before returning from main. As @chux pointed out in comment any character remaining in input buffer (enter from scanf in this case) must be cleared.

    #include <stdio.h>

    int main()

    {
       int a, b, c;

       printf("Enter two numbers to add\n");
       scanf("%d%d", &a, &b);

       c = a + b;

       printf("Sum of the numbers = %d\n", c);
       //clear input buffer
       int d;
       while ((d = getchar()) != '\n' && d != EOF) { }
       printf("Press ENTER key to Continue\n");  
       getchar(); 
       return 0;
    }

Upvotes: 3

F&#235;amarto
F&#235;amarto

Reputation: 314

CMD prompt just closes without warning and never spits out an answer

Seems like you are opening a new terminal on Windows machine. I compiled the code and it works. Your program closes just after printing the answer so you simply cannot see it. Stop it artificially before the end. To prove it add the following line directly before return:

scanf("%c", &a);

This will result in stopping the program and waiting for input. You will need to enter another number which will essentially be ignored but will stop the program so you can see the output. This is not a good target solution though due to you need to enter some characters to go on and exit but it proves the point :)

Upvotes: 1

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