39 lines
995 B
C
39 lines
995 B
C
/* A very simple subnet calculator in C, written by
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* Jack-Benny Persson (jack-benny@cyberinfo.se).
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* Released under GNU GPLv2.
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*/
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#include <stdio.h>
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#include <math.h>
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main()
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{
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int net;
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double hosts;
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double addr;
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printf("Enter netmask in slash-notation without the slash: ");
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scanf("%d", &net);
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if (net >= 0 && net <= 32) // Sanity check the user input
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{
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printf("Netmask bit: %d\n\n", net);
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addr = pow(2, 32-net); // Calculate number of addresses
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printf("%.0lf total addresses\n", addr);
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hosts = addr-2;
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if (hosts < 0) // Check if number of usable hosts is a negative value
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{
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hosts = 0; // Set usable hosts to zero if it was negative
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}
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printf("%.0lf usable addresses for hosts\n", hosts);
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return 0;
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}
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else // If the user entered anything else than 0-32
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{
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printf("Only values between 0-32 are accepted\n");
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return 1;
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}
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return 1;
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}
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