2 x Scanf (functions)

This is a discussion on 2 x Scanf (functions) within the C Programming forums, part of the General Programming Boards category; Whenever I call One scanf it works, then the second one, bypasses the whole scanf, and gives me the default ...

  1. #1
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    2 x Scanf (functions)

    Whenever I call One scanf it works, then the second one, bypasses the whole scanf, and gives me the default value for it


    how do we get around 2 scanf's?????

    help me someone smart!!!!

    thanks

    greg

  2. #2
    Registered User The Dog's Avatar
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    After every call to scanf(), you must flush the input buffer. Read the board's faq on how to flush the input buffer and why you must do it.

  3. #3
    Registered User Vber's Avatar
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    Search the board, many people asked a lot of times.
    anyway some people will tell you to use fgets() and then convert of specified type.

    you can see this here, it will work in a loop:
    Code:
    #include <stdio.h>
    #include <stdlib.h>
    
    int main(void) {
        char buf[BUFSIZ];
        int num;
        
        while(1) {
            printf("Enter a number: ");
            fgets(buf,sizeof(buf),stdin);
        
            num = atoi(buf); //converts the data
            printf("%d * 10 = %d\n",num,num*10);
        }
        
        system("PAUSE");
        return 0;
    }
    I'm not sure this is the best way, but search the board about the scanf() question, yes I know it's an infinite loop, it was just to show this will work in a loop. CTRL+C or CTRL+Z to stop the program.
    Last edited by Vber; 03-16-2003 at 08:00 AM.

  4. #4
    Registered User Codeplug's Avatar
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    Does any of this help you DrJones? I don't understand your problem, without more details or some sample code.

    gg

  5. #5
    C++ Developer XSquared's Avatar
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    Code:
    include <stdio.h>
    
    #define FLUSH_INPUT while( fgetc( stdin ) != '\n' )
    
    main( ) {
    
    	char string[256];
    	int n;
    
    	fscanf( stdin, "%s", string );  // Read in a string
    	FLUSH_INPUT; // Make sure the input buffer is empty
    	fscanf( stdin, "%d", &n ); // Read in a number
    	FLUSH_INPUT; // Make sure the input buffer is empty
    
    	fprintf( stdout, "%s\n%d\n", string, n );
    
    }
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