Unexpected change of input values

I tried a very simple code to add and subtract integer values using functions.
The code is listed below. When the user inputs a value for the 2nd Integer (int b in this case) it is automatically changed to a zero after the character input.. why does this happen ? The same code perfectly works when integers are substituted by floats.

Code:

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#include<stdio.h>
#include <conio.h>

int Add(int a,int b);
int Sub(int a,int b);

int main()
{
int a;
int b;
char typ;

printf("\n Value A:");
scanf("%d",&a);
printf("\n Value B:");
scanf("%d",&b);

printf("\n Which? + or - : ");
scanf("%s",&typ);
switch(typ)
{
case '+':printf("\n The Anser is: %d\n",Add(a,b));
break;
case '-':printf("\n The Anser is: %d\n",Sub(a,b));
break;
}
getch();
return 0;
}

int Add(int a,int b)
{
int add;
add=a+b;
return add;
}
int Sub(int a,int b)
{
int sub;
sub=a-b;
return sub;
}

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> scanf("%s",&typ);
Because your typ is only a single char, and any actual input you provide will take up at LEAST two characters, thus trashing someone elses memory. "%s" conversions append a \0 to everything they do.

> The same code perfectly works when integers are substituted by floats.
That just makes you lucky, not good.

>scanf("%s",&typ);
Because %s is the wrong format specifier for a char. %s is for char arrays, and %c for chars.

Code:

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scanf("%c",&typ);

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Code:

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scanf("%c",&typ);

---

%s is for strings

And i would really suspect that code would work properly. Since u have used scanf, it would give you a lot of problems, either when you port this code to a different machine.

You will have to fflush the input buffer before reading the char value that is + or -.

ssharish2005

printf("\n Which? + or - : "); // when the character input is shifted to the top it works fine..
scanf("%s",&typ); //plus %c did not work.. compiler used is bcc32

printf("\n Value A:");
scanf("%d",&a);
printf("\n Value B:");
scanf("%d",&b);

call this function before the you read the + or -

Code:

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void flush_buffer(void)
{
    int ch;
   
    while((ch=getchar()) != '\n' && ch != EOF);
}

---

ssharish2005