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  1.     #include <iostream>
  2.     #include <string.h>
  3.  
  4.     void foo(char* a, char* b){
  5.              char* temp = new char[strlen(a)+1];
  6.  
  7.              strcpy(temp, a);
  8.              std::cout << "temp = " << temp << " a = " << a << " b = " << b << std::endl;
  9.  
  10.              strcpy(a, b);
  11.              std::cout << "temp = " << temp << " a = " << a << " b = " << b << std::endl;
  12.  
  13.              strcpy(b, temp); // this copies 6 bytes to b, which puts a 0 in the first byte of a.
  14.              std::cout << "temp = " << temp << " a = " << a << " b = " << b << std::endl;
  15.  
  16.              delete[] temp;
  17.     }
  18.  
  19.     int main() {
  20.          char a[] = "First";
  21.          char b[] = "Last";
  22.  
  23.          std::cout << "a size is " << sizeof(a) << std::endl;
  24.          std::cout << "b size is " << sizeof(b) << std::endl;
  25.  
  26.          std::cout << "address of a[0] is " << (void*)&a[0] << std::endl;
  27.          std::cout << "address of b[0] is " << (void*)&b[0] << std::endl;
  28.  
  29.          foo(a, b);
  30.  
  31.          std::cout << "A After: "<< a << "\n";
  32.          std::cout << "B After: "<< b << "\n\n";
  33.     }
Success #stdin #stdout 0s 3432KB
comments (?)
stdin
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Standard input is empty
stdout
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a size is 6
b size is 5
address of a[0] is 0xbfe1ffaa
address of b[0] is 0xbfe1ffa5
temp = First a = First b = Last
temp = First a = Last b = Last
temp = First a =  b = First
A After: 
B After: First
https://ideone.com/fDvnnH
language:
C++14 (gcc 8.3)
created:
12 years ago
visibility:
secret

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