number_test.c

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

char *numbers[] = {
"123.456e-789",
"0.4e00669999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999969999999006",
"-1e+9999",
"1.5e+9999",
"-123123e100000",
"123123e100000",
"123e-1000000",
"-123123123123123123123123123123",
"100000000000000000000",
"-237462374673276894279832749832423479823246327846",
"0e+1",
"0e1",
"4",
"-0.000000000000000000000000000000000000000000000000000000000000000000000000000001",
"20e1",
"-0",
"-123",
"-1",
"-0",
"1E-2",
"1E+2",
"1E22",
"123e45",
"123.456e78",
"1e-2",
"1e+2",
"123",
"123.456789",
"123e65",
};

int main() {
    for (int i = 0; i < sizeof(numbers) / sizeof(numbers[0]); i++) {
        char *dummy;
        double result = strtod(numbers[i], &dummy);
        printf("%s = %f\n", numbers[i], result);
    }

    return 0;
}