why my program is giving garbage value in o/p after providing sufficient inputs? code is as follows:

Question

Why my program is giving garbage value in O/P after providing sufficient inputs?

I have given I/P as 10 & 40 & choose multiplication option as 3.

My code is as follows:

int main()
{
    int a,b,c,x;
    printf("Enter a & b \n");    //printing
    scanf("%d %d, &a,&b");
    printf("1. add \n 2. sub \n 3. multiply \n 4. div \n 5. mod \n 6. and \n 7. or\n 8. not \n 9. xor \n");
    printf("Enter your choice \n");
    scanf("%d, &x");

    switch(x)
    {
        case 1: c=a+b;
                break;

        case 2: c=a-b;
                break;

        case 3: c=a*b;
                break;

        case 4: c=a/b;
                break;

        case 5: c=a%b;
                break;

        case 6: c=a && b;
                break;

        case 7: c=a || b;
                break;        

        case 8: c=~a;
                break;

        case 9: c=a^b;
                break;

        default: printf("Make correct choice\n");
    }

    printf("result is: %d",c);
    return 0;
}

Answer 1

You are passing a string to scanf function in line number 5 & 8 and no buckets to hold the scanned/read arguments.

The scanf function's prototype is as follows:

int scanf(const char *format_string, ...);

Where the format_string is string containing format specifiers such as %d, %f...etc

And "..." in prototype means variable number of arguments. The arguments are buckets to hold the values that scanf fills by reading the format_string.

Hence the corrected lines of code should be

line 5.  scanf("%d %d", &a,&b);
line 8.  scanf("%d", &x);

Another notewothy thing is the variable arguments for scanf are always pointers to objects.

Answer 2

Syntax of scanf function is

scanf(“format string”, argument list); 

So for example, change

scanf("%d %d, &a,&b");
scanf("%d, &x");

to

scanf("%d %d", &a,&b);
scanf("%d", &x);

Answer 3

first of all your input nothing to be scan from your console or any other input.

please check scanf() sysntax.

#include<stdio.h>
int main()
{
 int a,b,c,x;
 printf("Enter a & b \n"); //printing 
 scanf("%d %d", &a, &b);
 printf("1. add \n 2. sub \n 3. multiply \n 4. div \n 5. mod \n 6. and \n 7. or\n 8. not \n 9. xor \n");
 printf("Enter your choice \n");
 scanf("%d", &x);
 switch(x)
 {
  case 1:   c=a+b;

    break;
 case 2:  c=a-b;

    break;
 case 3:  c=a*b;

    break;
case 4:  c=a/b;

    break;
case 5:  c=a%b;

     break;
case 6:  c=a && b;

     break;
case 7:  c=a || b;

      break;
case 8:  c=~a;

    break;
case 9:  c=a^b;

     break;
default: printf("Make correct choice\n");
}
  printf("result is: %d",c);
  return 0;
 }