2.1.17.2.2.3 Curve_x

1 Description
2 Syntax
3 Parameters
4 Return
5 Examples
6 Remark
7 See Also
8 Header to Include
9 Reference

Description

Get X value of Curve at specified index.

Syntax

double Curve_x( curvebase * pcrvData, int nIndex )

Parameters

pcrvData: [input] Pointer to Curve
nIndex: [input] Zero based index

Return

For given Curve returns value of X at specified value of nIndex.

If the given index is out of the range of the dataset, it returns NANUM.

Examples

EX1

// This is a self contained sample program for the function Curve_x, 
// Its sample data is created at the beginning of the program. 
// To run the program, enter the following command in the Script window:
//   Curve_x_ex1
// It returns like the following three lines:
//   Find X at Row#3 ==> FOUND: 4

void Curve_x_ex1()
{
    double dXatI;
    Worksheet wks;
    wks.Create();
    Dataset myXDs(wks,0);
    Dataset myYDs(wks,1);
    
    //******* Create sample data *****************
    myXDs.SetSize(4);
    myYDs.SetSize(4);
    myXDs[0]=1;    myYDs[0]=2;
    myXDs[1]=2;    myYDs[1]=4;
    myXDs[2]=4;    myYDs[2]=8;
    myXDs[3]=8;    myYDs[3]=16;
    //******** End of Sample Data Creation *******
    
    Curve crvData( myXDs, myYDs );    // Create Curve object

    int nIndex=2;       // 0-based index
    dXatI = Curve_x(&crvData,nIndex);    // Demonstration of Curve_x
    if(dXatI!=NANUM)
        printf( "Find X at Row#%d ==> FOUND: %g\n",nIndex+1,dXatI); // Row#=nIndex+1
    else 
        printf( "Find X at Row#%d ==> NOT FOUND\n",nIndex+1); // Row#=nIndex+1
}