Example: strlen

The following example loops through a string, str, in search of the first non-numeric character. strlen ascertains the length, len, of str. If the while loop has iterated len times, indicating the end of the string, then the loop terminates with a return statement.

    #include <string.h>
    int is_digit, i = 0;
    char * str = "1234567k89";
    unsigned int len = strlen(str);
    do {
        if (i == len) {
            lr_output_message ("No letters found in string");
            return -1;
        is_digit = isdigit(str[i++]);
    while (is_digit);
        lr_output_message ("The first letter appears in character %d of string", i);}
Example: Output:
Action.c(18): The first letter appears in character 8 of string