Question

Write an interactive program exam1 that loops
Loop and asks the user at the end of the loop to continue or not
Ask the user to enter an alphanumeric US phone number
Read the line of text from the screen
Check if the entered string is a valid phone number
using isValid(Line)
if it is valid number
{
call toNumeric(line) to convert it to digits
print Line after conversion
}

bool isValid(char line[])
{
//st must have 10 digits and letters
//ignore non-alpha like () . -
//first 3 should be digits like:
//800.got.milk
//use int size = strlen(line);
int alnumCount = 0;
return true or false
}

void toNumeric(char line[])
{
//use switvh statement
for size_t i=0; i<strlen(line); i++)
{
char ch = line[i];
ch = tolower(ch);
switch(ch)
{
case 'a':
case 'b':
case 'c':
line[i] = '2';
break;
.....
}
}
}

int exam1main(void)
{
Loop
read line
check if line is valid using isValid(line)
if valid call toNumber(line) to convert to digitis
printf line
Ask if you want to continue
return 0;
}

Answer 1

Please find the program to convert to numeric phone number and necessary comments in the program.

Program:

#include <stdio.h>
#include <string.h>
#include <stdbool.h>
#include <ctype.h>

#define SIZE 30

bool isValid(char line[])
{
  
//st must have 10 digits and letters
//ignore non-alpha like () . -
//first 3 should be digits like:
//800.got.milk
//use int size = strlen(line);
int alnumCount = 0;
int size = strlen(line);
int start =0;
  
//return false if the size is less than 10
if(size < 10)
{
return false;
}
  
//return false if the line does not have numbers for first three digits
if (!((line[0] >= '0' && line[0] <= '9') && (line[1] >= '0' && line[1] <= '9') &&
(line[2] >= '0' && line[2] <= '9')))
{
return false;
}
  
//count how many alphanumeric characters are present
while(start < size)
{
if (!(line[start] == '(' || line[start] == ')' || line[start] == '.'
|| line[start] == '-'))
{
  
alnumCount++;
}
start++;
}
  
//if it has ten characters, return true else false
//printf("%d", alnumCount);
if (alnumCount==10)
{
return true;
}
  
return false;
}

void toNumeric(char line[])
{
//use switvh statement
size_t i =0;
for (i=0; i<strlen(line); i++)
{
char ch = line[i];
ch = tolower(ch);
//convert only the characters to numbers
switch(ch)
{
case 'a':
case 'b':
case 'c':
line[i] = '2';
break;
case 'd':
case 'e':
case 'f':
line[i] = '3';
break;
case 'g':
case 'h':
case 'i':
line[i] = '4';
break;
case 'j':
case 'k':
case 'l':
line[i] = '5';
break;
case 'm':
case 'n':
case 'o':
line[i] = '6';
break;
case 'p':
case 'q':
case 'r':
case 's':
line[i] = '7';
break;
case 't':
case 'u':
case 'v':
line[i] = '8';
break;
case 'w':
case 'x':
case 'y':
case 'z':
line[i] = '9';
break;
default:
break;
}
}
}

int exam1main(void)
{
int continu=1, value;
char line[SIZE]={'\0',};
char answer[5]={'\0', };
  
while (continu)
{
printf("Enter Phone Number:\n");
  
//read the user input
scanf("%s", line);
/* if (fgets(line, SIZE, stdin) == NULL)
{
printf("Error in reading phoneNumber.\n");
return -1;
}
*/
  
//check if its a valid phone number
if(isValid(line))
{
//convert to numeric format
toNumeric(line);
printf("%s\n", line);
}
else
{
printf("Invalid phone Number.\n");
  
}
  
//do we need to continue check here
printf("Would you like to continue? (y/n): ");
scanf("%s", answer);
  
/* Ask user if they want to add another employee */
if ((value = toupper(answer[0])) != 'Y')
{
continu=0;
}
else
{
continu=1;
}
}
  
return 0;
}

//invoke main from here
int main()
{
exam1main();
return 0;
}

Output:

Enter Phone Number:
800-got-milk
800-468-6455
Would you like to continue? (y/n): y
Enter Phone Number:
1800COMPUTE
Invalid phone Number.
Would you like to continue? (y/n): n

Screen Shot:

Output ScreenShot: