C：printf中的额外输出

Question

I've just started to learn C programming last week and I've learnt about some basics about it. So now I'm trying to make a program which can add up two numbers and show the result. Here's my code:

#include <stdio.h>

int main (void)
{
    int a;
    int b;
    int result;

    printf("Insert a number:%d\n");
    scanf ("%d",&a);

    printf ("Insert the next number:%d\n");
    scanf ("%d",&b);

    result = a + b;

    printf ("Result is:%d\n",result);
    return 0;

}

It can be compiled and run but the following result is shown. [1] http://i.stack.imgur.com/4Xjdv.png

Can someone please help me to get rid of that 4200612, which is output at the first printf statement? Thanks for your help and sorry for my bad english.

Answer 1

There is no need of %d in first two printf statement.

printf("Insert a number: ");
scanf ("%d",&a);
printf ("Insert the next number: ");
scanf ("%d",&b);

Since there is no corresponding argument. It will print some random value.

Answer 2

Try getting rid of the extra %d's in your printfs.

#include <stdio.h>

int main (void)
{
    int a;
    int b;
    int result;

    printf("Insert a number:\n");
    scanf ("%d",&a);

    printf ("Insert the next number:\n");
    scanf ("%d",&b);

    result = a + b;

    printf ("Result is:%d\n",result);
    return 0;

}