// 10142009.cpp, P H Anderson, Oct 14, '09

#include <stdio.h>
#include <stdlib.h>
#include <string.h>   

typedef struct
{
    float x;
    float y;
} CPLX;
   
void capitalize_letter(char *s, int nth);
char up_case(char ch);
void replace_letter(char *s, char c1, char c2);
void reverse_str(char *s);
void swap_char(char *p1, char *p2);

void encrypt_str(char *s, int cipher);
void decrypt_str(char *s, int cipher);

CPLX fetch_complex(void);

int main()
{
    char s[50];
    CPLX z1;
    
    strcpy(s, "what's the story?");
    capitalize_letter(s, 4);
    printf("PT #1 %s\n", s);
    replace_letter(s, 'a', 'b');
    printf("PT #2 %s\n", s);
    reverse_str(s);
    printf("PT #3%s\n", s);
    
    encrypt_str(s, 5);
    printf("PT #4 %s\n", s);
    decrypt_str(s, 5);
    printf("PT #5%s\n", s);
    
    z1 = fetch_complex();
    printf("%.2f %.2f\n", z1.x, z1.y);
    
    system("pause");     
}
     
void capitalize_letter(char *s, int nth)
{ // stub
    s[3] = up_case(s[3]);
}

char up_case(char ch)
{ // stub
    return('A');
}
void replace_letter(char *s, char c1, char c2)
{ // stub
   s[0] = 'X';   
}
void reverse_str(char *s)
{  // stub
   int len;
   len = strlen(s);
   swap_char(&s[0], &s[len - 1]);
}

void swap_char(char *p1, char *p2)
{
    char tmp;
    tmp = *p1;
    *p1 = *p2;
    *p1 = tmp;    
}

void encrypt_str(char *s, int cipher)
{ // stub
   s[0] = s[0] + 5;  
}
void decrypt_str(char *s, int cipher)
{ // stub
    s[0] = s[0] - 5;
}

CPLX fetch_complex(void)
{
    CPLX q;
    float a, b;
    printf("Enter real and imag: ");
    scanf("%f %f", &q.x, &q.y);
    return(q);
}

#ifdef OUTPUT
PT #1 whaA's the story?
PT #2 XhaA's the story?
PT #3XhaA's the story?
PT #4 ]haA's the story?
PT #5XhaA's the story?
Enter real and imag: 3 4
3.00 4.00
Press any key to continue . . .
#endif
</pre>