If in a string at some index there is a number and I want to store it another variable then why we do int n=str[i]-'0'?

Asked Nov 21 '20 at 18:17

Active Nov 21 '20 at 18:19

Viewed 28 times

I tried without '0' and got error,Please explain it.

getline(cin,str);
int n=str[4]-'0';

edited Nov 21 '20 at 18:19

John Kugelman

asked Nov 21 '20 at 18:17

Coding Beginner

The string has the digit's ascii value. Also, the ascii values for all digits are contiguous. So to convert from the ascii value to the digit value, you can subtract the ascii value of '0'. – L. Scott Johnson Nov 21 '20 at 18:20
The ASCII value of '0' is 48 and that of '9' is 57. Basically, any number (literal) you encounter is in between and hence the subtraction does the job. – Abin Thomas Nov 21 '20 at 18:23

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