How to swap two numbers without using any other variable or function in C++?

[SubhanUllah]

For numbers its pretty easy. Addition is reversible. For other types of data, not to much:

#include <cstdio> 
int main() { 
    int a = 123; 
    int b = 44; 
    float c = -2.234; 
    float d = 4.456; 
    printf("%-18s %11s %14s\n"," ","a  <->  b","c  <->  d"); 
    printf("%-15s %7d\t%7d\t%7.3f\t%7.3f\n","Starting values",a,b,c,d); 
    a = a + b; // a has both numbers 
    c = c + d; // c now is both numbers 
    printf("%-15s %7d\t%7d\t%7.3f\t%7.3f\n","a = a + b",a,b,c,d); 
    b = a - b; // b now has a 
    d = c - d; // d now has c 
    printf("%-15s %7d\t%7d\t%7.3f\t%7.3f\n","b = a - b",a,b,c,d); 
    a = a - b; // a now has b 
    c = c - d; // c now had d 
    printf("%-15s %7d\t%7d\t%7.3f\t%7.3f\n","a = a - b",a,b,c,d); 
} 
Output:

                     a  <->  b      c  <->  d 
Starting values     123            44        -2.234         4.456 
a = a + b           167            44         2.222         4.456 
b = a - b           167           123         2.222        -2.234 
a = a - b            44           123         4.456        -2.234