I need help completing this C code. Basically it asks user for input String and reverses it and changes cases.

#include %26lt;stdio.h%26gt;





char* strRev(char* line);


//your code here


char* str2Lower(char* line);





main(void){


//your code here


while(opt != 4){


printf("\n--------------------------...


printf("\nCST220 --- Assignment 2\n");


printf("Joe Smith XXX-YY-ZZZZ\n\n");


printf("Please choose the type operation\n");


printf("1. Reverse an string\n");


printf("2. Change an string to upper case\n");


printf("3. Change an string to lower case\n");


printf("4. End application (Exit)\n");


printf("Option: ");


scanf("%d", %26amp;opt);





if(opt != 4 %26amp;%26amp; (opt %26gt;= 1 %26amp;%26amp; opt %26lt;= 3)){


printf("\n\nPlease enter the string: ");


//your code here


if(opt == 1){


printf("\nThe reversed string is : %s", strRev(str));


}


else if(opt == 2){


printf("\nThe string in uppercase: %s", str2Upper(str));


}


else if(opt == 3){


printf("\nThe string in lowercase: %s", str2Lower(str));


}


}


}


}


char* strRev(char* line){


//your code here


return str2;


}





char* str2Upper(char* line){


//your code here


return str2;


}





char* str2Lower(char* line){


//your code here


return str2;


}

I need help completing this C code. Basically it asks user for input String and reverses it and changes cases.
#include %26lt;ctype.h%26gt;





char* strRev(char* line) {


char *str2, first;


str2 = line+strlen(line)-1;


while (str2%26gt;line) {


first = line;


*line = str2;


*str2 = first;


line++;


str2--;


}


return str2;


}





char* str2Upper(char* line) {


while( *line ) {


*line = toupper(*line);


line++;


}


return line;


}





char* str2Lower(char* line) {


while( *line ) {


*line = tolower(*line);


line++;


}


return line;


}