How can we convert a string to int for very large integer values?

Question

I have used the function atoi to convert character strings to int and it\'s working fine but when I gave

num = atoi (argv[1]) ;

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Answer 1

You've run into the maximum value of an integer. Since atoi returns an int, it is limited to the size of an integer on your machine. It looks like your machine uses 32-bit ints.

In case you missed it (it's easy to miss), 2147483647 = (2 ^ 31) - 1. Remember that ints can be negative, and the leftmost bit is the sign bit in that case. That's why you see the number being "limited" to 2147483647.

Try defining num as unsigned int instead of int, and use strtoul instead of atoi.