# include # include # include # include using namespace std; int main ( ); int search ( int a, int b, int c ); int f ( int i ); //****************************************************************************80 int main ( ) //****************************************************************************80 // // Purpose: // // MAIN is the main program for SEARCH. // // Licensing: // // This code is distributed under the GNU LGPL license. // // Modified: // // 22 October 2012 // // Author: // // John Burkardt // { int a; int b; int c; int fj; int i4_huge = 2147483647; int j; double wtime = 0.0; a = 1; b = i4_huge; c = 45; cout << "\n"; cout << "SEARCH:\n"; cout << " C++ version\n"; cout << " Search the integers from A to B\n"; cout << " for a value J such that F(J) = C.\n"; cout << "\n"; cout << " A = " << a << "\n"; cout << " B = " << b << "\n"; cout << " C = " << c << "\n"; //wtime = ???; j = search ( a, b, c ); //wtime = ?? - wtime; if ( j == -1 ) { cout << "\n"; cout << " No solution was found.\n"; } else { cout << "\n"; cout << " Found J = " << j << "\n"; cout << " Verify F(J) = " << f ( j ) << "\n"; } //cout << " Elapsed time is " << wtime << "\n"; // // Terminate. // cout << "\n"; cout << "SEARCH:\n"; cout << " Normal end of execution.\n"; return 0; } //****************************************************************************80 int search ( int a, int b, int c ) //****************************************************************************80 // // Purpose: // // SEARCH searches integers in [A,B] for a J so that F(J) = C. // // Licensing: // // This code is distributed under the GNU LGPL license. // // Modified: // // 22 October 2012 // // Author: // // John Burkardt // // Parameters: // // Input, int A, B, the search range. // // Input, int C, the desired function value. // // Output, int SEARCH, the computed solution, or -1 // if no solution was found. // { int fi; int i; int j; j = -1; for ( i = a; i <= b; i++ ) { fi = f ( i ); if ( fi == c ) { j = i; break; } } return j; } //****************************************************************************80 int f ( int i ) //****************************************************************************80 // // Purpose: // // F is the function we are analyzing. // // Licensing: // // This code is distributed under the GNU LGPL license. // // Modified: // // 22 October 2012 // // Author: // // John Burkardt // // Parameters: // // Input, int I, the argument. // // Input, int F, the value. // { int i4_huge = 2147483647; int j; int k; int value; value = i; for ( j = 1; j <= 5; j++ ) { k = value / 127773; value = 16807 * ( value - k * 127773 ) - k * 2836; if ( value <= 0 ) { value = value + i4_huge; } } return value; }