binary to decimal

[mast3124mind]

hi this is my code. The code should convert binary numbers to decimal but it doesn't...can any1 please check where i could have gone wrong.

#include <stdio.h>
#include <math.h>
#include <string.h>
int main()
{
     
    char s[40];
    int base;
    int index,n,p,sum=0;     /*n is the number of digits in the converted value*/
    
    printf("enter the number and base: ");
    scanf("%s %d",s,&base);
    
    for(n=strlen(s)-1;n>=0;n--)
    {
        p=strlen(s);
        for(index=strlen(s)-(p-1); index<=p; index++)
        sum += s[index] * pow(base,n);
    }
    printf("%d",sum);
    printf("\n");

}

[jwroblewski44]

If you are looking to convert only binary numbers into only the decimal format, why are you asking the user for a base? For the sake of simplicity, remove the user input factor and just hard-code numbers into a string and focus on converting from binary to decimal.

Adjust your code and re-post.

[stahta01]

Why do you have two for loops?

Tim S.

[mast3124mind]

There you go man...

#include <stdio.h>
#include <math.h>
#include <string.h>
int main()
{
      
    char s[40];
    int base=2;

    int index,n,p,sum=0;     /*n is the number of digits in the converted value*/
     
    printf("enter your binary number:");

    scanf("%s",s);

     
    for(n=strlen(s)-1;n>=0;n--)
    {
        p=strlen(s);
        for(index=strlen(s)-(p-1); index<=p; index++)
        sum += s[index] * pow(base,n);
    }
    printf("%d",sum);
    printf("\n");
 
}

[jwroblewski44]

Logic would be, declare a counter and initialize to zero, then start at the end of the string. For every bit, multiply by "2 raised to the counter variable" and add to sum( are you sure you're currently raising to the right power? ), then increment the counter.

As stahta01 said, you should only need one loop to accomplish this.

One more thing: you are calling strlen multiple times on the same string when you only need to call it once and save it to a variable.

There YOU​ go...............man.