Input time in $12-$hour notation and print out the corresponding $24-$hour notation. There are several steps.

Name your source code convert$\_12\_$to$\_24.$cpp

Input time in $12-$hour notation to a string variable.

$($a$)$ The format of $12-$hour notation is hh:mm AM or hh:mm PM $,$ where hh is in $1,12$ and mm is in $0,59,$

the input may contain space.

We cannot use cin $$ variablellame; to read the input, since $$ stops at the first space or return

key, whichever is encounted first.

To read input with spaces, use getline$($cin$,$ variablellame$)$; read a line, and put the input line to

veriablellame.

Operator $$ read an int, a double number, a string, cdots, to the corresponding variable.

Function getline read a line and save that line to a string variable.

Extract the last two characters from input, it should be either AM or PM$.$

Extract values of hour and minute from input.

$($a$)$ Use find method of string class to find out the index of colon $($i$),$ a character separating hour and

minute.

$($b$)$ Use substr method of string class to get the substring representing hour and minute.

$($c$)$ Use stoi function to convert a string to the corresponding integers. For example, sto$1("12")$ returns

If hour is not in $1,12($that is$,$ hour is smaller than $0$ or hour is larger than $12)$ or minute is not in $0,59,$

then print "invalid input" and return$-1.$ The word "invalid" cannot be missed.

$($a$)$ Optional $($will not test in gradescope script$)$: test whether input is ended with either $"$AM$"$ or $"$PM$".$

Depending on the values of suffix $"$AM$"$ or $"$PM$"$ and hour, print out the corresponding $24-$hour notation.