C++ Programming Code Examples
C++ > Beginners Lab Assignments Code Examples
program in C++ to generate random integers in a specific range.
/* program in C++ to generate random integers in a specific range. */
#include <cstdlib>
#include <ctime>
#include <iostream>
using namespace std;
int main()
{
int ln,un;
cout << "\n\n Generate random integer in a specific range: \n";
cout << " --------------------------------------------------\n";
cout << " Input the lower range of number: ";
cin >> ln;
cout << " Input the upper range of number: ";
cin >> un;
srand(time(NULL));
cout<<" The random number between "<<ln<<" and "<<un<<" is: ";
cout << ln+rand() % static_cast<int>(un-ln+1) << endl;
return 0;
}
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Initialize random number generator. The pseudo-random number generator is initialized using the argument passed as seed. The C++ <cstdlib> srand() function seeds the pseudo-random number generator used by rand() function. If rand() is used before any calls to srand(), rand() behaves as if it was seeded with srand(1). For every different seed value used in a call to srand, the pseudo-random number generator can be expected to generate a different succession of results in the subsequent calls to rand. Two different initializations with the same seed will generate the same succession of results in subsequent calls to rand. If seed is set to 1, the generator is reinitialized to its initial value and produces the same values as before any call to rand or srand.
Consider a situation, when we have two persons with the same name, jhon, in the same class. Whenever we need to differentiate them definitely we would have to use some additional information along with their name, like either the area, if they live in different area or their mother's or father's name, etc. Same situation can arise in your C++ applications. For example, you might be writing some code that has a function called xyz() and there is another library available which is also having same function xyz(). Now the compiler has no way of knowing which version of xyz() function you are referring to within your code.
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