Using - C
  
 Source Code
  

    
#include<stdio.h>
#include<math.h>
#include<string.h>

void convertToDecimal(char binary[ ]);

void main() {
	int i;
	char binary[1024];
	printf("Enter binary number:  ");
	gets(binary);
	printf("BINARY :  %s",binary);
	convertToDecimal(binary);
}

void convertToDecimal(char binary[ ]) {
	int i, eqv_decimal = 0, length = strlen(binary);
	strrev(binary);
	
	for(i=0; i < length; i++) {	
		if(binary[i]=='1') {
		eqv_decimal += pow(2,i);	
		}	
	}
	printf("\nDECIMAL:  %d", eqv_decimal);
}
    

Enter binary number:  101
BINARY   :  101
DECIMAL:  5

        
Using - C++
        
 Source Code
        

        
#include<iostream>
#include<math.h>
#include<string.h>
#include<algorithm>
using namespace std;

void convertToDecimal(string binary);

int main() {
	string binary;
	cout<< "Enter binary number:  ";
	getline(cin,binary);
	
	cout<<"BINARY :  "<< binary;
	convertToDecimal(binary);
		
	return 0;
}

void convertToDecimal(string binary) {
	int eqv_decimal = 0, length = binary.length();
	reverse(binary.begin(), binary.end());
	
	for(int i=0; i < length; i++) {	
		if(binary[i]=='1') {
			eqv_decimal += pow(2,i);	
		}	
	}
	cout<< "\nDECIMAL:  "<< eqv_decimal;
}      

Enter binary number:  101110
BINARY   :  101110
DECIMAL:  46