Question

Write a C program as follows:

• Single source code file
• Uses an infinite loop
• Requests the user to press a key
• Uses a nested switch statement
• Either prints the key pressed, or terminates using the break statement and prints Goodbye! if the user presses either the e or E key

Please include lots of comments please, this is how I learn how to code. I need LOTS of comments!

Answer 1

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CODE:

#include <stdio.h>
#include <stdlib.h>

int main()
{
char ch; //Character variable to store user's input character
int exit_flag=0; //Flag used to exit from the infinite loop. The loop is exited when it's value is 1.
while(1) //Infinite flag. Any value other than 0 is evaluated to true. Hence loop with while(0) is never executed
{
printf("Enter a character:"); //Prompting the user to press key.
scanf(" %c",&ch); //Taking the user input and storing it in variable ch. Here we are passing the address of ch (&ch) so that scanf can change the actual value of ch.
switch(ch) //Switch block
{
case 'e': //When ch=='e', the program control comes here and then continues through the body of switch statement till a break statement is found. Since no break statement is found here, it moves to the next code i.e, code of case 'E'.
case 'E': //When ch=='E'
printf("Goodbye!"); //Printing the output
exit_flag=1; //Setting the flag to 1
break; //Breaks the program flow out of the switch block
default: //When ch!='e' && ch!='E'
printf("Entered character:%c\n",ch); //Outputting the entered key
}
if(exit_flag==1) //If the flag is set to 1, i.e, exit the loop
break; //Breaking out of the infinite loop
}
return 0;
}

OUTPUT: