math problem

This is a discussion on math problem within the C Programming forums, part of the General Programming Boards category; hi there im trying to make a math program the input is a/b # c/d # = / or + ...

  1. #1
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    Question math problem

    hi there im trying to make a math program
    the input is

    a/b # c/d

    # = / or + or - or *


    example

    input
    1/4 / 1/4
    output
    1
    input
    2/7 - 4/14
    output
    0
    input
    4/5 + 4/7
    output
    1 13/35
    input
    2/3 * 4/5
    output
    8/15


    this is my code for only + sign math program
    Code:
    #include <stdio.h>
    #include <conio.h>
    
    int main(void){
        int a, b, c, d, e, f, g;
        
        scanf("%d/%d%d/%d", &a, &b, &c, &d);
        b > 0;
        d > 0;
        
        e = (a * d) + (b * c);
        f = b * d;
        
        if(e < f)
        printf("%d/%d + %d/%d = %d/%d", a, b, c, d, e, f);
        if(e > f)
        printf("%d/%d + %d/%d = %d %d/%d", a, b, c, d, e / f, e % f, f);
        if(e == f)
        printf("%d/%d + %d/%d = 1", a, b, c, d);
        
        return 1;
        }
    my question is how to replace # in input with / or * or + or -

    sorry for my bad english tq

  2. #2
    Registered User claudiu's Avatar
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    Just read the # as a character in between your %d/%d in scanf. The flag for character is %c. Then, depending on what character you have read, you will know what calculation you need to perform.
    1. Get rid of gets(). Never ever ever use it again. Replace it with fgets() and use that instead.
    2. Get rid of void main and replace it with int main(void) and return 0 at the end of the function.
    3. Get rid of conio.h and other antiquated DOS crap headers.
    4. Don't cast the return value of malloc, even if you always always always make sure that stdlib.h is included.

  3. #3
    Registered User gaurav9991's Avatar
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    hi there im trying to make a math program
    the input is

    a/b # c/d

    # = / or + or - or *

    example

    input
    1/4 / 1/4 = 0 / 0 = ?
    output
    1

    input
    2/7 - 4/14 = 0 - 0 = 0
    output
    0

    input
    4/5 + 4/7 = 0 + 0 = 0
    output
    1 13/35

    input
    2/3 * 4/5 = 0 * 0 = 0
    output
    8/15

    you have declared a,b,c,d,e as integer variables which gives output as 0 for these situations.

    had it been (5/4)/(8/3) = (1.25) / (2.666) = (1) / (2) = 0

    corrected code is

    Code:
    #include <stdio.h>
    
    int main(void)
    {
        int a, b, c, d, e;
    	char hash;
        
     	printf("\n\nEnter a,b,c,d : ");   
    	scanf("%d%d%d%d", &a, &b, &c, &d);
        
    	printf("Enter # : ");	
    	
    	fflush(stdin);
    	scanf("%c",&hash);
    	
    	switch(hash)
    	{
    		case '/' :
    				e = (a/b)/(c/d);
    				break;	
    		case '*' :
    				e = (a/b)*(c/d);				
    				break;
    		case '+' :
    				e = (a/b)+(c/d);				
    				break;	
    		case '-' :
    				e = (a/b)-(c/d);				
    				break;
    		default :
    				printf("\n\nInvalid operator");
    	
    	}
    	
    	printf("\n\n   (%d/%d)%c(%d/%d) = %d \n\n",a,b,hash,c,d,e);
    
        return 0; 
    }
    thank you

  4. #4
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    thx man!
    now i understand

  5. #5
    Registered User claudiu's Avatar
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    Gurav:

    Don't ever fflush(stdin).

    Don't provide complete solutions to people who ask questions. It defeats the purpose of learning.
    1. Get rid of gets(). Never ever ever use it again. Replace it with fgets() and use that instead.
    2. Get rid of void main and replace it with int main(void) and return 0 at the end of the function.
    3. Get rid of conio.h and other antiquated DOS crap headers.
    4. Don't cast the return value of malloc, even if you always always always make sure that stdlib.h is included.

  6. #6
    Registered User gaurav9991's Avatar
    Join Date
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    Don't ever fflush(stdin)

    why ?

  7. #7
    Registered User claudiu's Avatar
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    Because it triggers undefined behavior. Read here:

    Cprogramming.com FAQ > Why fflush(stdin) is wrong
    1. Get rid of gets(). Never ever ever use it again. Replace it with fgets() and use that instead.
    2. Get rid of void main and replace it with int main(void) and return 0 at the end of the function.
    3. Get rid of conio.h and other antiquated DOS crap headers.
    4. Don't cast the return value of malloc, even if you always always always make sure that stdlib.h is included.

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