用這樣一組數(shù)字，0，1，1，2，3，5，8........，求第100個(gè)數(shù)是多少！

初看這道題很簡單，我們只需要設(shè)定一個(gè)數(shù)組，然后往里面放入對(duì)應(yīng)的值，除了前兩個(gè)數(shù)字位，后面每個(gè)數(shù)字位都是前兩個(gè)數(shù)字位的和。剛開始我用了int數(shù)組來存放這組數(shù)，發(fā)現(xiàn)根本放不下去，到了第47位數(shù)的時(shí)候就存在數(shù)值溢出了，然后我換為long型數(shù)組，同樣放不下去，到了第93位數(shù)的時(shí)候也存在數(shù)值溢出了。這樣，只能用BigInteger類了，這是java提供的可以存儲(chǔ)任意精度的整數(shù)的類，用它我們不需要考慮數(shù)值溢出的錯(cuò)誤。即使我們求第1000個(gè)數(shù)值也沒有什么問題。不過，它的數(shù)值運(yùn)算必須以方法調(diào)用方式取代運(yùn)算符方式來實(shí)現(xiàn)，由于這么做復(fù)雜了許多，運(yùn)算速度會(huì)比較慢，所以在確定數(shù)值不會(huì)溢出的情況下，是不推薦用這種型式來進(jìn)行數(shù)值存儲(chǔ)和運(yùn)算的。以下是具體代碼。

補(bǔ)充知識(shí)：

System.out.println("Integer的最大值："+Integer.MAX_VALUE); System.out.println("Long的最大值："+Long.MAX_VALUE); Integer的最大值：2147483647 //10位（十進(jìn)制） Long的最大值：9223372036854775807 //19位（十進(jìn)制） <pre code_snippet_id="642896" snippet_file_name="blog_20150517_2_2813945" name="code" class="java">BigInteger類型無限制大，故沒最大值

package test;import java.math.BigInteger;public class BigIntegertest {public static void main(String[] args) {int num = 100;//整型數(shù)組int[] resultInt = new int[100];resultInt[0] = 0;resultInt[1] = 1;//長整型數(shù)組long[] resultLong = new long[100];resultLong[0] = 0L;resultLong[1] = 1L;//BigInteger數(shù)組BigInteger[] resultBigInteger = new BigInteger[100];resultBigInteger[0] = BigInteger.ZERO;resultBigInteger[1] = BigInteger.ONE;for (int i = 2; i < num; i++) {resultInt[i] = resultInt[i - 1] + resultInt[i - 2];resultLong[i] = resultLong[i - 1] + resultLong[i - 2];resultBigInteger[i] = resultBigInteger[i - 1].add(resultBigInteger[i - 2]);}System.out.println("--------------------用整型來存儲(chǔ)數(shù)值的結(jié)果！---------------------");for (int i = 0; i < resultInt.length; i++) {System.out.println("resultInt[" + i + "] = "+ resultInt[i]);}System.out.println("--------------------用長整型來存儲(chǔ)數(shù)值的結(jié)果！---------------------");for (int i = 0; i < resultLong.length; i++) {System.out.println("resultLong[" + i + "] = "+ resultLong[i]);}System.out.println("--------------------用BigInteger來存儲(chǔ)數(shù)值的結(jié)果！---------------------");for (int i = 0; i < resultBigInteger.length; i++) {System.out.println("resultBigInteger[" + i + "] = "+ resultBigInteger[i]);}} } 結(jié)果：

--------------------用整型來存儲(chǔ)數(shù)值的結(jié)果！--------------------- resultInt[0] = 0 resultInt[1] = 1 resultInt[2] = 1 resultInt[3] = 2 resultInt[4] = 3 resultInt[5] = 5 resultInt[6] = 8 resultInt[7] = 13 resultInt[8] = 21 resultInt[9] = 34 resultInt[10] = 55 resultInt[11] = 89 resultInt[12] = 144 resultInt[13] = 233 resultInt[14] = 377 resultInt[15] = 610 resultInt[16] = 987 resultInt[17] = 1597 resultInt[18] = 2584 resultInt[19] = 4181 resultInt[20] = 6765 resultInt[21] = 10946 resultInt[22] = 17711 resultInt[23] = 28657 resultInt[24] = 46368 resultInt[25] = 75025 resultInt[26] = 121393 resultInt[27] = 196418 resultInt[28] = 317811 resultInt[29] = 514229 resultInt[30] = 832040 resultInt[31] = 1346269 resultInt[32] = 2178309 resultInt[33] = 3524578 resultInt[34] = 5702887 resultInt[35] = 9227465 resultInt[36] = 14930352 resultInt[37] = 24157817 resultInt[38] = 39088169 resultInt[39] = 63245986 resultInt[40] = 102334155 resultInt[41] = 165580141 resultInt[42] = 267914296 resultInt[43] = 433494437 resultInt[44] = 701408733 resultInt[45] = 1134903170 resultInt[46] = 1836311903 resultInt[47] = -1323752223 resultInt[48] = 512559680 resultInt[49] = -811192543 resultInt[50] = -298632863 resultInt[51] = -1109825406 resultInt[52] = -1408458269 resultInt[53] = 1776683621 resultInt[54] = 368225352 resultInt[55] = 2144908973 resultInt[56] = -1781832971 resultInt[57] = 363076002 resultInt[58] = -1418756969 resultInt[59] = -1055680967 resultInt[60] = 1820529360 resultInt[61] = 764848393 resultInt[62] = -1709589543 resultInt[63] = -944741150 resultInt[64] = 1640636603 resultInt[65] = 695895453 resultInt[66] = -1958435240 resultInt[67] = -1262539787 resultInt[68] = 1073992269 resultInt[69] = -188547518 resultInt[70] = 885444751 resultInt[71] = 696897233 resultInt[72] = 1582341984 resultInt[73] = -2015728079 resultInt[74] = -433386095 resultInt[75] = 1845853122 resultInt[76] = 1412467027 resultInt[77] = -1036647147 resultInt[78] = 375819880 resultInt[79] = -660827267 resultInt[80] = -285007387 resultInt[81] = -945834654 resultInt[82] = -1230842041 resultInt[83] = 2118290601 resultInt[84] = 887448560 resultInt[85] = -1289228135 resultInt[86] = -401779575 resultInt[87] = -1691007710 resultInt[88] = -2092787285 resultInt[89] = 511172301 resultInt[90] = -1581614984 resultInt[91] = -1070442683 resultInt[92] = 1642909629 resultInt[93] = 572466946 resultInt[94] = -2079590721 resultInt[95] = -1507123775 resultInt[96] = 708252800 resultInt[97] = -798870975 resultInt[98] = -90618175 resultInt[99] = -889489150 --------------------用長整型來存儲(chǔ)數(shù)值的結(jié)果！--------------------- resultLong[0] = 0 resultLong[1] = 1 resultLong[2] = 1 resultLong[3] = 2 resultLong[4] = 3 resultLong[5] = 5 resultLong[6] = 8 resultLong[7] = 13 resultLong[8] = 21 resultLong[9] = 34 resultLong[10] = 55 resultLong[11] = 89 resultLong[12] = 144 resultLong[13] = 233 resultLong[14] = 377 resultLong[15] = 610 resultLong[16] = 987 resultLong[17] = 1597 resultLong[18] = 2584 resultLong[19] = 4181 resultLong[20] = 6765 resultLong[21] = 10946 resultLong[22] = 17711 resultLong[23] = 28657 resultLong[24] = 46368 resultLong[25] = 75025 resultLong[26] = 121393 resultLong[27] = 196418 resultLong[28] = 317811 resultLong[29] = 514229 resultLong[30] = 832040 resultLong[31] = 1346269 resultLong[32] = 2178309 resultLong[33] = 3524578 resultLong[34] = 5702887 resultLong[35] = 9227465 resultLong[36] = 14930352 resultLong[37] = 24157817 resultLong[38] = 39088169 resultLong[39] = 63245986 resultLong[40] = 102334155 resultLong[41] = 165580141 resultLong[42] = 267914296 resultLong[43] = 433494437 resultLong[44] = 701408733 resultLong[45] = 1134903170 resultLong[46] = 1836311903 resultLong[47] = 2971215073 resultLong[48] = 4807526976 resultLong[49] = 7778742049 resultLong[50] = 12586269025 resultLong[51] = 20365011074 resultLong[52] = 32951280099 resultLong[53] = 53316291173 resultLong[54] = 86267571272 resultLong[55] = 139583862445 resultLong[56] = 225851433717 resultLong[57] = 365435296162 resultLong[58] = 591286729879 resultLong[59] = 956722026041 resultLong[60] = 1548008755920 resultLong[61] = 2504730781961 resultLong[62] = 4052739537881 resultLong[63] = 6557470319842 resultLong[64] = 10610209857723 resultLong[65] = 17167680177565 resultLong[66] = 27777890035288 resultLong[67] = 44945570212853 resultLong[68] = 72723460248141 resultLong[69] = 117669030460994 resultLong[70] = 190392490709135 resultLong[71] = 308061521170129 resultLong[72] = 498454011879264 resultLong[73] = 806515533049393 resultLong[74] = 1304969544928657 resultLong[75] = 2111485077978050 resultLong[76] = 3416454622906707 resultLong[77] = 5527939700884757 resultLong[78] = 8944394323791464 resultLong[79] = 14472334024676221 resultLong[80] = 23416728348467685 resultLong[81] = 37889062373143906 resultLong[82] = 61305790721611591 resultLong[83] = 99194853094755497 resultLong[84] = 160500643816367088 resultLong[85] = 259695496911122585 resultLong[86] = 420196140727489673 resultLong[87] = 679891637638612258 resultLong[88] = 1100087778366101931 resultLong[89] = 1779979416004714189 resultLong[90] = 2880067194370816120 resultLong[91] = 4660046610375530309 resultLong[92] = 7540113804746346429 resultLong[93] = -6246583658587674878 resultLong[94] = 1293530146158671551 resultLong[95] = -4953053512429003327 resultLong[96] = -3659523366270331776 resultLong[97] = -8612576878699335103 resultLong[98] = 6174643828739884737 resultLong[99] = -2437933049959450366 --------------------用BigInteger來存儲(chǔ)數(shù)值的結(jié)果！--------------------- resultBigInteger[0] = 0 resultBigInteger[1] = 1 resultBigInteger[2] = 1 resultBigInteger[3] = 2 resultBigInteger[4] = 3 resultBigInteger[5] = 5 resultBigInteger[6] = 8 resultBigInteger[7] = 13 resultBigInteger[8] = 21 resultBigInteger[9] = 34 resultBigInteger[10] = 55 resultBigInteger[11] = 89 resultBigInteger[12] = 144 resultBigInteger[13] = 233 resultBigInteger[14] = 377 resultBigInteger[15] = 610 resultBigInteger[16] = 987 resultBigInteger[17] = 1597 resultBigInteger[18] = 2584 resultBigInteger[19] = 4181 resultBigInteger[20] = 6765 resultBigInteger[21] = 10946 resultBigInteger[22] = 17711 resultBigInteger[23] = 28657 resultBigInteger[24] = 46368 resultBigInteger[25] = 75025 resultBigInteger[26] = 121393 resultBigInteger[27] = 196418 resultBigInteger[28] = 317811 resultBigInteger[29] = 514229 resultBigInteger[30] = 832040 resultBigInteger[31] = 1346269 resultBigInteger[32] = 2178309 resultBigInteger[33] = 3524578 resultBigInteger[34] = 5702887 resultBigInteger[35] = 9227465 resultBigInteger[36] = 14930352 resultBigInteger[37] = 24157817 resultBigInteger[38] = 39088169 resultBigInteger[39] = 63245986 resultBigInteger[40] = 102334155 resultBigInteger[41] = 165580141 resultBigInteger[42] = 267914296 resultBigInteger[43] = 433494437 resultBigInteger[44] = 701408733 resultBigInteger[45] = 1134903170 resultBigInteger[46] = 1836311903 resultBigInteger[47] = 2971215073 resultBigInteger[48] = 4807526976 resultBigInteger[49] = 7778742049 resultBigInteger[50] = 12586269025 resultBigInteger[51] = 20365011074 resultBigInteger[52] = 32951280099 resultBigInteger[53] = 53316291173 resultBigInteger[54] = 86267571272 resultBigInteger[55] = 139583862445 resultBigInteger[56] = 225851433717 resultBigInteger[57] = 365435296162 resultBigInteger[58] = 591286729879 resultBigInteger[59] = 956722026041 resultBigInteger[60] = 1548008755920 resultBigInteger[61] = 2504730781961 resultBigInteger[62] = 4052739537881 resultBigInteger[63] = 6557470319842 resultBigInteger[64] = 10610209857723 resultBigInteger[65] = 17167680177565 resultBigInteger[66] = 27777890035288 resultBigInteger[67] = 44945570212853 resultBigInteger[68] = 72723460248141 resultBigInteger[69] = 117669030460994 resultBigInteger[70] = 190392490709135 resultBigInteger[71] = 308061521170129 resultBigInteger[72] = 498454011879264 resultBigInteger[73] = 806515533049393 resultBigInteger[74] = 1304969544928657 resultBigInteger[75] = 2111485077978050 resultBigInteger[76] = 3416454622906707 resultBigInteger[77] = 5527939700884757 resultBigInteger[78] = 8944394323791464 resultBigInteger[79] = 14472334024676221 resultBigInteger[80] = 23416728348467685 resultBigInteger[81] = 37889062373143906 resultBigInteger[82] = 61305790721611591 resultBigInteger[83] = 99194853094755497 resultBigInteger[84] = 160500643816367088 resultBigInteger[85] = 259695496911122585 resultBigInteger[86] = 420196140727489673 resultBigInteger[87] = 679891637638612258 resultBigInteger[88] = 1100087778366101931 resultBigInteger[89] = 1779979416004714189 resultBigInteger[90] = 2880067194370816120 resultBigInteger[91] = 4660046610375530309 resultBigInteger[92] = 7540113804746346429 resultBigInteger[93] = 12200160415121876738 resultBigInteger[94] = 19740274219868223167 resultBigInteger[95] = 31940434634990099905 resultBigInteger[96] = 51680708854858323072 resultBigInteger[97] = 83621143489848422977 resultBigInteger[98] = 135301852344706746049 resultBigInteger[99] = 218922995834555169026補(bǔ)充：int[]和long[] 發(fā)生溢出但并沒有報(bào)錯(cuò)，而是給了一個(gè)錯(cuò)誤的結(jié)果，改進(jìn)方法如下。

long l =10000000000000L;if(l > Integer.MAX_VALUE){throw new Exception("超出int范圍");}else{System.out.println((int)l);}

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