61 lines
1.5 KiB
C++
61 lines
1.5 KiB
C++
// leftover.cpp -- overloading the left() function
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#include <iostream>
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unsigned long left(unsigned long num, unsigned ct);
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char * left(const char * str, int n = 1);
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int main()
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{
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using namespace std;
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char * trip = "Hawaii!!"; // test value
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unsigned long n = 12345678; // test value
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int i;
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char * temp;
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for (i = 1; i < 10; i++)
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{
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cout << left(n, i) << endl;
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temp = left(trip,i);
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cout << temp << endl;
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delete [] temp; // point to temporary storage
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}
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// cin.get();
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return 0;
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}
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// This function returns the first ct digits of the number num.
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unsigned long left(unsigned long num, unsigned ct)
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{
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unsigned digits = 1;
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unsigned long n = num;
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if (ct == 0 || num == 0)
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return 0; // return 0 if no digits
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while (n /= 10)
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digits++;
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if (digits > ct)
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{
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ct = digits - ct;
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while (ct--)
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num /= 10;
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return num; // return left ct digits
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}
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else // if ct >= number of digits
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return num; // return the whole number
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}
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// This function returns a pointer to a new string
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// consisting of the first n characters in the str string.
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char * left(const char * str, int n)
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{
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if(n < 0)
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n = 0;
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char * p = new char[n+1];
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int i;
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for (i = 0; i < n && str[i]; i++)
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p[i] = str[i]; // copy characters
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while (i <= n)
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p[i++] = '\0'; // set rest of string to '\0'
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return p;
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}
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