C Programming Absolute Beginner's Guide (3rd Edition)

// getchar() is defined in stdio.h, but string.h is needed for the

// strlen() function

#include <stdio.h>

#include <string.h>

main()

{

int i;

char msg[25];

printf("Type up to 25 characters and then press Enter...\n");

for (i = 0; i < 25; i++)

{

msg[i] = getchar(); //Outputs a single character

if (msg[i] == '\n')

{

i--;

break;

}

}

putchar('\n'); // One line break after the loop is done.

for (; i >= 0; i--)

{

putchar(msg[i]);

}

putchar('\n');

return(0);

}

Note

Notice that the second for loop variable i has no initial value. Actually, it does. i

contains the last array subscript entered in the previous getchar() for loop.

Therefore, the second for loop continues with the value of i left by the first for

loop.

The getchar() input character typically is defined as an int, as done here. Integers and
characters are about the only C data types you can use interchangeably without worry of typecasts. In
some advanced applications, getchar() can return a value that won’t work in a char data type,
so you’re safe if you use int.

Aren’t you glad you learned about break? The program keeps getting a character at a time until the
user presses Enter (which produces a newline \n escape sequence). break stops the loop.

The Newline Consideration