C program to calculate no. of significant digits and rounding off the number if it is a floating number

C program to calculate no. of significant digits and rounding off the number if it is a floating number

 

#include<stdio.h>
#include<string.h>
using namespace std;

int main()
{
char s[200];
scanf("%s",&s);
int l,i,j,n,d,c=0;
l=strlen(s);
for(i=l-1;i>=0;--i)
    {
    if(s[i]!='0')break;
    }
j=i;
for(i=0;s[i]!='.';++i)
    {
    if(s[i]!='0')break;
    --j;
    }
for(i=0;i<l;++i)
    if(s[i]=='.')
        c=1;
if(!c)
    {
    ++j;
    printf("Number of significant digits are %d",j);
    goto end;
    }
printf("Number of significant digits are %d \n How many Significant Digits you want(Should not be less than decimal place)?\n",j);

scanf("%d",&n);
d=j-n;
for(i=l-1;i>=0;--i)
    if(s[i]!='0')
        break;
    else
        s[i]='-';

while(d--)
    {
    if(s[i]=='.')
        {
        s[i]='-';
        continue;
        }
    else if(s[i]>'5')
        {
        s[i-1]=char(int(s[i-1])+1);
       s[i]='-';
        }
else if(s[i]<'5')
    {
    s[i]='-';
    }
else if(s[i]=='5')
    {
    if((int(s[i-1]))%2)
        {
        s[i]='-';
        }
    else
        {
       s[i-1]=char(int(s[i-1])+1);
       s[i]='-';
        }
    }
--i;
    }
for(i=0;i<l;++i)
    if(s[i]!='-')
        printf("%c",s[i]);
end:
return 0;
}