|4.20.4.Use scanf to get input from a standard input device, such as a keyboard|
In scanf, you have to specify the address of a variable, such as &i, &j, and a list of format specifiers (%d).
The number of format specifiers must be the same as the number of variables.
printf("Input two integers and press Enter to comfirm:");
k = i + j;
printf("sum of two numbers is %d \n",k);
Input two integers and press Enter to comfirm:223
sum of two numbers is 225