strtoul : strtoul « stdlib.h « C Tutorial

1. C Tutorial
2. stdlib.h
3. strtoul

1. If radix is zero, the base is determined by the rules that govern constant specification.
2. If the radix is specified, it must be in the range 2 through 36.

Reads unsigned base 16 (hexadecimal) numbers from standard input and returns their unsigned long equivalent:

#include <stdlib.h>

int main(void){

    char *start, *end;
    char a[100];

    end = a;
    *start= "12341234";
    printf("%d", strtoul(start, &end, 8));

}

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