CODEWITHSUNDEEP
carraysstringatoi
Dilip Kumar
Dilip Kumar

Reputation: 1746

string to individual numbers

I ran across a problem where I need to extract each element of string to an integer array, the string only contains integer values without any space or delimiter.

Here is an example. 

char input[8]="02320000";

to

int output[8]={0,2,3,2,0,0,0,0};

I tried to use the atoi() and it is taking the entire string as digit.

The string characters will be 0-3.

thank you

Upvotes: 1

Views: 254

Answers (2)

Pablo
Pablo

Reputation: 13580

Well, you can loop through all characters of the string:

char input[8]="02320000";
char output[8];

for(int = 0; i < 8; ++i)
    output[i] = input[i] - '0';

Strings in C are just sequences of characters that ends with the so called '\0'-terminating byte, whose value is 0. We use char arrays to store them and we use the ASCII values for the character.

Note that 1 != '1'. 1 is the interger one, '1' is the representation of the number one. The representation has the value 49 (see ASCII). If you want to calculate the real number of a character representation, you have to use c-'0', where c is the character in question. That works because in the table, the values of the numbers also are ordered as the numbers themselves: '0' is 48, '1' is 49, '2' is 50, etc.

Upvotes: 2

pm100
pm100

Reputation: 50190

char input[8]="02320000";
int output[8];

for(int i = 0; i < 8; i++)
{
     output[i] = input[i] - '0';
}

explanation of the -'0' Convert a character digit to the corresponding integer in C

Upvotes: 3

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