Question

how to convert a digit in string into its equivalent int number?
for ecample to convert a[i]=3 to int b=3?

Answer 1

substract the ascii of 0 from your ascii
like if a[i]=3
a[i]-'0'
ascii of 3 is 51 and 0 is 49
51-49 =3 will give you integer eqivalent

Answer 2

ok thanks I will try it?

Answer 3

I am not getting it if it cross 9 then how to convert it into int?
that is to convert a[i]=20 to int 20?

Answer 4

ok there is a inbuild funciton atoi that will do your purpose

try this code

#include<stdio.h>
#include<stdlib.h>

int main ()
{
int i;
char buffer [256];

printf ("Enter a number: ");
fgets (buffer, 256, stdin);

i = atoi (buffer);
printf ("The value entered is %d.",i);

return 0;
}

Answer 5

or creating your own atoi
but it wont handle the -ve numbers



int myAtoi(char *str)
{
int res = 0; // Initialize result

// Iterate through all characters of input string and update result
for (int i = 0; str[i] != '\0'; ++i)
res = res*10 + str[i] - '0';

// return result.
return res;
}

Answer 6

@03225186213 hope you get it

Answer 7

why you multiplied res by 10

Answer 8

@nubeer

Answer 9

As you go through a string, you can have more than one number. you multiply by 10 to make them land in the right spot.
string i[] = "253"

i[0] = 2
i[1] = 5
i[2] = 3

2+5+3 = 10

\(10\ne 253\)

\((2*10+5)*10+3 \implies \)
\((20+5)*10+3 \implies \)
\(25*10+3 \implies \)
\(250+3 \implies \)
\(253 = \)"253"

Get why the * 10 now?