Sample - Conversion from Fractional String Value to Decimal Double:

#include <string.h> 
#include "stdlib.h"       
#include "iostream.h"     

void FractionalValueToDouble( char * pInitialString ,  double & dResult );

void main()
{
	double dResult;
	char szFraction[100];

	cout << "Enter fractional value like 5/7: ";
	cin >> szFraction;

	FractionalValueToDouble( szFraction, dResult );

	cout << "Double Result: ";
	cout << dResult << endl;
}


void FractionalValueToDouble( char * pInitialString , \
		              double & dResult )
{
	char szLeftPart[100];  
	char szRightPart[100]; 
	char * pSlash;

	int iLeftPart;
	int iRightPart;

	int iLeftPartLen;
	int iRightPartLen;

	pSlash =  strchr( pInitialString, '/' );

	iRightPartLen = strlen(pSlash+1);

        for( int i=0; i <  iRightPartLen; i++ )
	{
		szRightPart[i] = *(pSlash + 1 + i);
	}

	szRightPart[i] = '\0';
	
	iRightPart = atoi( szRightPart );


        iLeftPartLen = pSlash - pInitialString;

        for( i=0; i <  iLeftPartLen; i++ )
	{
		szLeftPart[i] = *(pInitialString +i);
	}

	szLeftPart[i] = '\0';
	
	iLeftPart = atoi( szLeftPart );

        dResult = (double)iLeftPart/(double)iRightPart; 
}

Input:

Enter fractional value like 5/7: 3/64

Output:

0.046875

(c) 2001, Stan Malevanny