Download lab$4.$py and rename it according to the instructions above.

Modify the program by adding the four missing functions. The functions are described in the grading section below.

If the missing functions are implemented correctly, this output will appear when the user enters how now brown cow for the first string and ow for the second string. Note: Your solution should work for any pair of strings.

output:

Enter a first string: how now brown cow

Enter a second string: ow

String Concatenation Testing

$----------------------------$

Using built$-$in $+$: how now brown cowow

Using concatenation$\_$loop function: how now brown cowow

Using concatenation$\_$recursion function: how now brown cowow

Occurences of Second String in First String Testing

$---------------------------------------------------$

Using built$-$in count: $4$

Using occurrences$\_$loop function: $4$

Using occurrences$\_$recursion function: $4$

full code:

### main

def main$()$:

$"""$ This tests the four required functions. Do not change this code. $"""$

print$("$CSCI $127,$ Lab $4")$

print$("---------------")$

string$\_1=$ input$("$Enter a first string: $").$lower$()$

string$\_2=$ input$("$Enter a second string: $").$lower$()$

print$("$

String Concatenation Testing"$)$

print$("----------------------------")$

print$("$Using built$-$in $+$: $",$ string$\_1+$ string$\_2)$

print$("$Using concatenation$\_$loop function: $",\backslash$

concatenation$\_$loop$($string$\_1,$ string$\_2))$

print$("$Using concatenation$\_$recursion function: $",\backslash$

concatenation$\_$recursion$($string$\_1,$ string$\_2))$

###

print$("$

Occurences of Second String in First String Testing"$)$

print$("---------------------------------------------------")$

print$("$Using built$-$in count: $",$ string$\_1.$count$($string$\_2))$

print$("$Using occurrences$\_$loop function: $",\backslash$

occurrences$\_$loop$($string$\_1,$ string$\_2))$

print$("$Using occurrences$\_$recursion function: $",\backslash$

occurrences$\_$recursion$($string$\_1,$ string$\_2))$

# $---------------------------------------$

main$()$

grading:

$4$ points $-$ A function named concatenation$\_$loop is implemented that has two string parameters. The function must return the concatenation of the two strings using an appropriate loop. You may use the built$-$in concatenation operator $(+)$ to concatenate a string and a character. However, you may not use it to concatenate two strings.

$1$ point $-$ A function named concatenation$\_$recursion is implemented that has two string parameters. The function must return the concatenation of the two strings using recursion. You may use the built$-$in concatenation operator $(+)$ to concatenate a string and a character. However, you may not use it to concatenate two strings. Do not use any loops in the solution.

$4$ points $-$ A function named occurrences$\_$loop is implemented that has two string parameters. The function must return the number of times that the second string parameter appears in the first using an appropriate loop. The built$-$in count function may not be used.

$1$ point $-$ A function named occurrences$\_$recursion is implemented that has two string parameters. The function must return the number of times that the second string parameter appears in the first using recursion. Neither the built$-$in count function nor any loops may be used.