Programming Compiler

This assignment gives an opportunity to practice pointer and string manipulation. You should not call any existing string function from C++ string library. You need to implement three function defined as I do in copy function. //compare string s1 and s2, return 1 if s1>s2, return –1 if s1<s2,

//return 0 if s1 equal to s2

int strcmp(const char* s1,const char* s2);

//return the string length of string s

int length(const char* s);

//return the number of times character “c” in string “s”

int countChar(const char* s,const char c);

The main function is provided as: #include<iostream>

using namespace std;

int strcmp(const char*,const char*);

int length(const char*);

int countChar(const char*,const char);

void copy(char*, const char*); void menu();

void main()

{

char s1[20],s2[20];

bool done=false;

char c;

int choice;

while(!done){

menu();

cin>>choice;

switch(choice){

case 1:

cout<<"Please enter two strings\n";

cin>>s1>>s2;

if(strcmp(s1,s2)>0)

cout<<"\""<<s1<<"\" is greater than \""<<s2<<"\"\n";

else if(strcmp(s1,s2)<0)

cout<<"\""<<s1<<"\" is less than \""<<s2<<"\"\n";

else

cout<<"\""<<s1<<"\" is equal to \""<<s2<<"\"\n";

break;

case 2:

cout<<"Please enter a string\n";

cin>>s1;

cout<<"Length of \""<<s1<<"\" is "<<length(s1)<<endl;

break;

case 3:

cout<<"Please enter a string and a charater\n";

cin>>s1>>c;

cout<<c<<" appear in \""<<s1<<"\" "<<countChar(s1,c)

<<" times\n";

break;

case 4:

cout<<"Please enter a string\n"; cin>>s1; copy(s2,s1); cout<<"s2 now is "<<s2<<"\n"; break; case 5: done=true; break; default:

cout<<"Wrong option!\n";

}

}

}

void menu()

{

cout<<"Please enter one of the following\n"

<<"1. Compare two strings\n"

<<"2. Find string length\n"

<<"3. Count char in string\n"

<<"4. Quit"<<endl;

}

void copy(char* s1,const char* s2){ while(*s2!=0){ *s1=*s2;//copy a character from s2 to s1 s1++;//now s1 points to the next position s2++;//now s2 points to the next character } *s1='\0';//set end mark ; }

int strcmp(const char* s1,const char* s2)

{

/* add your code here*/

}

int length(const char* s)

{

/*add your code here*/

}

int countChar(const char*s,const char c)

{

/*add your code here*/

}