C++ 变量作用域

一般来说有三个地方可以定义变量：

• 在函数或一个代码块内部声明的变量，称为局部变量。

• 在函数参数的定义中声明的变量，称为形式参数。

• 在所有函数外部声明的变量，称为全局变量。

作用域是程序的一个区域，变量的作用域可以分为以下几种：

• 局部作用域：在函数内部声明的变量具有局部作用域，它们只能在函数内部访问。局部变量在函数每次被调用时被创建，在函数执行完后被销毁。

• 全局作用域：在所有函数和代码块之外声明的变量具有全局作用域，它们可以被程序中的任何函数访问。全局变量在程序开始时被创建，在程序结束时被销毁。

• 块作用域：在代码块内部声明的变量具有块作用域，它们只能在代码块内部访问。块作用域变量在代码块每次被执行时被创建，在代码块执行完后被销毁。

• 类作用域：在类内部声明的变量具有类作用域，它们可以被类的所有成员函数访问。类作用域变量的生命周期与类的生命周期相同。

注意：如果在内部作用域中声明的变量与外部作用域中的变量同名，则内部作用域中的变量将覆盖外部作用域中的变量。

局部变量

https://avg.163.com/M/topic/detail/12640276
https://avg.163.com/topic/detail/12640869
https://avg.163.com/M/topic/detail/12640869
https://avg.163.com/topic/detail/12640867
https://avg.163.com/M/topic/detail/12640867
https://avg.163.com/topic/detail/12640335
https://avg.163.com/M/topic/detail/12640335
https://avg.163.com/topic/detail/12640866
https://avg.163.com/M/topic/detail/12640866
https://avg.163.com/topic/detail/12640860
https://avg.163.com/M/topic/detail/12640860
https://avg.163.com/topic/detail/12640854
https://avg.163.com/M/topic/detail/12640854
https://avg.163.com/topic/detail/12640326
https://avg.163.com/M/topic/detail/12640326
https://avg.163.com/topic/detail/12640314
https://avg.163.com/M/topic/detail/12640314
https://avg.163.com/topic/detail/12640274
https://avg.163.com/M/topic/detail/12640274
https://avg.163.com/topic/detail/12640313
https://avg.163.com/M/topic/detail/12640313
https://avg.163.com/topic/detail/12640315
https://avg.163.com/M/topic/detail/12640315
https://avg.163.com/topic/detail/12640312
https://avg.163.com/M/topic/detail/12640312
https://avg.163.com/topic/detail/12640305
https://avg.163.com/M/topic/detail/12640305
https://avg.163.com/topic/detail/12640383
https://avg.163.com/M/topic/detail/12640383
https://avg.163.com/topic/detail/12640303
https://avg.163.com/M/topic/detail/12640303
https://avg.163.com/topic/detail/12640822
https://avg.163.com/M/topic/detail/12640822
https://avg.163.com/topic/detail/12640820
https://avg.163.com/M/topic/detail/12640820
https://avg.163.com/topic/detail/12640812
https://avg.163.com/M/topic/detail/12640812
https://avg.163.com/topic/detail/12640810
https://avg.163.com/M/topic/detail/12640810
https://avg.163.com/topic/detail/12640813
https://avg.163.com/M/topic/detail/12640813
https://avg.163.com/topic/detail/12640806
https://avg.163.com/M/topic/detail/12640806
https://avg.163.com/topic/detail/12640795
https://avg.163.com/M/topic/detail/12640795
https://avg.163.com/topic/detail/12640275
https://avg.163.com/M/topic/detail/12640275
https://avg.163.com/topic/detail/12640250
https://avg.163.com/M/topic/detail/12640250
https://avg.163.com/topic/detail/12640270
https://avg.163.com/M/topic/detail/12640270
https://avg.163.com/topic/detail/12640278
https://avg.163.com/M/topic/detail/12640278
https://avg.163.com/topic/detail/12640281
https://avg.163.com/M/topic/detail/12640281
https://avg.163.com/topic/detail/12640267
https://avg.163.com/M/topic/detail/12640267
https://avg.163.com/topic/detail/12640787
https://avg.163.com/M/topic/detail/12640787
https://avg.163.com/topic/detail/12640263
https://avg.163.com/M/topic/detail/12640263
https://avg.163.com/topic/detail/12640271
https://avg.163.com/M/topic/detail/12640271
https://avg.163.com/topic/detail/12640272
https://avg.163.com/M/topic/detail/12640272
https://avg.163.com/topic/detail/12640257
https://avg.163.com/M/topic/detail/12640257
https://avg.163.com/topic/detail/12640262
https://avg.163.com/M/topic/detail/12640262
https://avg.163.com/topic/detail/12640264
https://avg.163.com/M/topic/detail/12640264
https://avg.163.com/topic/detail/12640774
https://avg.163.com/M/topic/detail/12640774
https://avg.163.com/topic/detail/12640751
https://avg.163.com/M/topic/detail/12640751
https://avg.163.com/topic/detail/12640266
https://avg.163.com/M/topic/detail/12640266
https://avg.163.com/topic/detail/12640256
https://avg.163.com/M/topic/detail/12640256
https://avg.163.com/topic/detail/12640259
https://avg.163.com/M/topic/detail/12640259
https://avg.163.com/topic/detail/12640219
https://avg.163.com/M/topic/detail/12640219
https://avg.163.com/topic/detail/12640260
https://avg.163.com/M/topic/detail/12640260
https://avg.163.com/topic/detail/12640227
https://avg.163.com/M/topic/detail/12640227
https://avg.163.com/topic/detail/12640253
https://avg.163.com/M/topic/detail/12640253
https://avg.163.com/topic/detail/12640726
https://avg.163.com/M/topic/detail/12640726
https://avg.163.com/topic/detail/12640714
https://avg.163.com/M/topic/detail/12640714
https://avg.163.com/topic/detail/12640729
https://avg.163.com/M/topic/detail/12640729
https://avg.163.com/topic/detail/12640725
https://avg.163.com/M/topic/detail/12640725
https://avg.163.com/topic/detail/12640720
https://avg.163.com/M/topic/detail/12640720
https://avg.163.com/topic/detail/12640175
https://avg.163.com/M/topic/detail/12640175
https://avg.163.com/topic/detail/12640254
https://avg.163.com/M/topic/detail/12640254
https://avg.163.com/topic/detail/12640179
https://avg.163.com/M/topic/detail/12640179
https://avg.163.com/topic/detail/12640187
https://avg.163.com/M/topic/detail/12640187
https://avg.163.com/topic/detail/12640202
https://avg.163.com/M/topic/detail/12640202
https://avg.163.com/topic/detail/12640204
https://avg.163.com/M/topic/detail/12640204
https://avg.163.com/topic/detail/12640223
https://avg.163.com/M/topic/detail/12640223
https://avg.163.com/topic/detail/12640224
https://avg.163.com/M/topic/detail/12640224
https://avg.163.com/topic/detail/12640198
https://avg.163.com/M/topic/detail/12640198
https://avg.163.com/topic/detail/12640688
https://avg.163.com/M/topic/detail/12640688
https://avg.163.com/topic/detail/12640690
https://avg.163.com/M/topic/detail/12640690
https://avg.163.com/topic/detail/12640684
https://avg.163.com/M/topic/detail/12640684
https://avg.163.com/topic/detail/12640682
https://avg.163.com/M/topic/detail/12640682
https://avg.163.com/topic/detail/12640675
https://avg.163.com/M/topic/detail/12640675
https://avg.163.com/topic/detail/12640170
https://avg.163.com/M/topic/detail/12640170
https://avg.163.com/topic/detail/12640205
https://avg.163.com/M/topic/detail/12640205
https://avg.163.com/topic/detail/12640176
https://avg.163.com/M/topic/detail/12640176
https://avg.163.com/topic/detail/12640186
https://avg.163.com/M/topic/detail/12640186
https://avg.163.com/topic/detail/12640221
https://avg.163.com/M/topic/detail/12640221
https://avg.163.com/topic/detail/12640206
https://avg.163.com/M/topic/detail/12640206
https://avg.163.com/topic/detail/12640207
https://avg.163.com/M/topic/detail/12640207
https://avg.163.com/topic/detail/12640210
https://avg.163.com/M/topic/detail/12640210
https://avg.163.com/topic/detail/12640190
https://avg.163.com/M/topic/detail/12640190
https://avg.163.com/topic/detail/12640662
https://avg.163.com/M/topic/detail/12640662
https://avg.163.com/topic/detail/12640180
https://avg.163.com/M/topic/detail/12640180
https://avg.163.com/topic/detail/12640217
https://avg.163.com/M/topic/detail/12640217
https://avg.163.com/topic/detail/12640638
https://avg.163.com/M/topic/detail/12640638
https://avg.163.com/topic/detail/12640178
https://avg.163.com/M/topic/detail/12640178
https://avg.163.com/topic/detail/12640124
https://avg.163.com/M/topic/detail/12640124
https://avg.163.com/topic/detail/12640619
https://avg.163.com/M/topic/detail/12640619
https://avg.163.com/topic/detail/12640191
https://avg.163.com/M/topic/detail/12640191
https://avg.163.com/topic/detail/12640137
https://avg.163.com/M/topic/detail/12640137
https://avg.163.com/topic/detail/12640173
https://avg.163.com/M/topic/detail/12640173
https://avg.163.com/topic/detail/12640576
https://avg.163.com/M/topic/detail/12640576
https://avg.163.com/topic/detail/12640160
https://avg.163.com/M/topic/detail/12640160
https://avg.163.com/topic/detail/12640158
https://avg.163.com/M/topic/detail/12640158
https://avg.163.com/topic/detail/12640120
https://avg.163.com/M/topic/detail/12640120
https://avg.163.com/topic/detail/12640177
https://avg.163.com/M/topic/detail/12640177
https://avg.163.com/topic/detail/12640151
https://avg.163.com/M/topic/detail/12640151
https://avg.163.com/topic/detail/12640580
https://avg.163.com/M/topic/detail/12640580
https://avg.163.com/topic/detail/12640578
https://avg.163.com/M/topic/detail/12640578
https://avg.163.com/topic/detail/12640139
https://avg.163.com/M/topic/detail/12640139
https://avg.163.com/topic/detail/12640573
https://avg.163.com/M/topic/detail/12640573
https://avg.163.com/topic/detail/12640568
https://avg.163.com/M/topic/detail/12640568
https://avg.163.com/topic/detail/12640564
https://avg.163.com/M/topic/detail/12640564
https://avg.163.com/topic/detail/12640558
https://avg.163.com/M/topic/detail/12640558
https://avg.163.com/topic/detail/12640562
https://avg.163.com/M/topic/detail/12640562
https://avg.163.com/topic/detail/12640554
https://avg.163.com/M/topic/detail/12640554
https://avg.163.com/topic/detail/12640049
https://avg.163.com/M/topic/detail/12640049
https://avg.163.com/topic/detail/12640143
https://avg.163.com/M/topic/detail/12640143
https://avg.163.com/topic/detail/12640129
https://avg.163.com/M/topic/detail/12640129
https://avg.163.com/topic/detail/12640148
https://avg.163.com/M/topic/detail/12640148
https://avg.163.com/topic/detail/12640136
https://avg.163.com/M/topic/detail/12640136
https://avg.163.com/topic/detail/12640125
https://avg.163.com/M/topic/detail/12640125
https://avg.163.com/topic/detail/12640132
https://avg.163.com/M/topic/detail/12640132
https://avg.163.com/topic/detail/12640131
https://avg.163.com/M/topic/detail/12640131
https://avg.163.com/topic/detail/12640528
https://avg.163.com/M/topic/detail/12640528
https://avg.163.com/topic/detail/12640537
https://avg.163.com/M/topic/detail/12640537
https://avg.163.com/topic/detail/12640532
https://avg.163.com/M/topic/detail/12640532
https://avg.163.com/topic/detail/12640055
https://avg.163.com/M/topic/detail/12640055
https://avg.163.com/topic/detail/12640162
https://avg.163.com/M/topic/detail/12640162
https://avg.163.com/topic/detail/12640121
https://avg.163.com/M/topic/detail/12640121
https://avg.163.com/topic/detail/12640115
https://avg.163.com/M/topic/detail/12640115
https://avg.163.com/topic/detail/12640123
https://avg.163.com/M/topic/detail/12640123
https://avg.163.com/topic/detail/12640122
https://avg.163.com/M/topic/detail/12640122
https://avg.163.com/topic/detail/12640522
https://avg.163.com/M/topic/detail/12640522
https://avg.163.com/topic/detail/12450220
https://avg.163.com/M/topic/detail/12450220
https://avg.163.com/topic/detail/12640044
https://avg.163.com/M/topic/detail/12640044
https://avg.163.com/topic/detail/12640130
https://avg.163.com/M/topic/detail/12640130
https://avg.163.com/topic/detail/12640052
https://avg.163.com/M/topic/detail/12640052
https://avg.163.com/topic/detail/12640514
https://avg.163.com/M/topic/detail/12640514
https://avg.163.com/topic/detail/12640512
https://avg.163.com/M/topic/detail/12640512
https://avg.163.com/topic/detail/12640480
https://avg.163.com/M/topic/detail/12640480
https://avg.163.com/topic/detail/12640506
https://avg.163.com/M/topic/detail/12640506
https://avg.163.com/topic/detail/12640076
https://avg.163.com/M/topic/detail/12640076
https://avg.163.com/topic/detail/12640077
https://avg.163.com/M/topic/detail/12640077
https://avg.163.com/topic/detail/12640054
https://avg.163.com/M/topic/detail/12640054
https://avg.163.com/topic/detail/12640482
https://avg.163.com/M/topic/detail/12640482
https://avg.163.com/topic/detail/12640484
https://avg.163.com/M/topic/detail/12640484
https://avg.163.com/topic/detail/12640036
https://avg.163.com/M/topic/detail/12640036
https://avg.163.com/topic/detail/12640472
https://avg.163.com/M/topic/detail/12640472
https://avg.163.com/topic/detail/12640471
https://avg.163.com/M/topic/detail/12640471
https://avg.163.com/topic/detail/12640470
https://avg.163.com/M/topic/detail/12640470
https://avg.163.com/topic/detail/12640467
https://avg.163.com/M/topic/detail/12640467
https://avg.163.com/topic/detail/12640469
https://avg.163.com/M/topic/detail/12640469
https://avg.163.com/topic/detail/12640468
https://avg.163.com/M/topic/detail/12640468
https://avg.163.com/topic/detail/12640466
https://avg.163.com/M/topic/detail/12640466
https://avg.163.com/topic/detail/12640465
https://avg.163.com/M/topic/detail/12640465
https://avg.163.com/topic/detail/12640464
https://avg.163.com/M/topic/detail/12640464
https://avg.163.com/topic/detail/12640066
https://avg.163.com/M/topic/detail/12640066
https://avg.163.com/topic/detail/12640462
https://avg.163.com/M/topic/detail/12640462
https://avg.163.com/topic/detail/12640153
https://avg.163.com/M/topic/detail/12640153
https://avg.163.com/topic/detail/12640094
https://avg.163.com/M/topic/detail/12640094
https://avg.163.com/topic/detail/12450134
https://avg.163.com/M/topic/detail/12450134
https://avg.163.com/topic/detail/12640449
https://avg.163.com/M/topic/detail/12640449
https://avg.163.com/topic/detail/12640447
https://avg.163.com/M/topic/detail/12640447
https://avg.163.com/topic/detail/12640441
https://avg.163.com/M/topic/detail/12640441
https://avg.163.com/topic/detail/12640434
https://avg.163.com/M/topic/detail/12640434
https://avg.163.com/topic/detail/12640430
https://avg.163.com/M/topic/detail/12640430
https://avg.163.com/topic/detail/12640432
https://avg.163.com/M/topic/detail/12640432
https://avg.163.com/topic/detail/12640102
https://avg.163.com/M/topic/detail/12640102
https://avg.163.com/topic/detail/12640045
https://avg.163.com/M/topic/detail/12640045
https://avg.163.com/topic/detail/12640038
https://avg.163.com/M/topic/detail/12640038
https://avg.163.com/topic/detail/12640079
https://avg.163.com/M/topic/detail/12640079
https://avg.163.com/topic/detail/12640090
https://avg.163.com/M/topic/detail/12640090
https://avg.163.com/topic/detail/12640127
https://avg.163.com/M/topic/detail/12640127
https://avg.163.com/topic/detail/12640062
https://avg.163.com/M/topic/detail/12640062
https://avg.163.com/topic/detail/12640096
https://avg.163.com/M/topic/detail/12640096
https://avg.163.com/topic/detail/12640097
https://avg.163.com/M/topic/detail/12640097
https://avg.163.com/topic/detail/12640030
https://avg.163.com/M/topic/detail/12640030
https://avg.163.com/topic/detail/12640111
https://avg.163.com/M/topic/detail/12640111
https://avg.163.com/topic/detail/12640106
https://avg.163.com/M/topic/detail/12640106
https://avg.163.com/topic/detail/12640118
https://avg.163.com/M/topic/detail/12640118
https://avg.163.com/topic/detail/12640113
https://avg.163.com/M/topic/detail/12640113
https://avg.163.com/topic/detail/12640100
https://avg.163.com/M/topic/detail/12640100
https://avg.163.com/topic/detail/12640108
https://avg.163.com/M/topic/detail/12640108
https://avg.163.com/topic/detail/12640064
https://avg.163.com/M/topic/detail/12640064
https://avg.163.com/topic/detail/12640414
https://avg.163.com/M/topic/detail/12640414
https://avg.163.com/topic/detail/12640415
https://avg.163.com/M/topic/detail/12640415
https://avg.163.com/topic/detail/12450143
https://avg.163.com/M/topic/detail/12450143
https://avg.163.com/topic/detail/12640411
https://avg.163.com/M/topic/detail/12640411
https://avg.163.com/topic/detail/12640410
https://avg.163.com/M/topic/detail/12640410
https://avg.163.com/topic/detail/12450128
https://avg.163.com/M/topic/detail/12450128
https://avg.163.com/topic/detail/12450131
https://avg.163.com/M/topic/detail/12450131
https://avg.163.com/topic/detail/12450116
https://avg.163.com/M/topic/detail/12450116
https://avg.163.com/topic/detail/12450136
https://avg.163.com/M/topic/detail/12450136
https://avg.163.com/topic/detail/12450145
https://avg.163.com/M/topic/detail/12450145
https://avg.163.com/topic/detail/12450127
https://avg.163.com/M/topic/detail/12450127
https://avg.163.com/topic/detail/12450159
https://avg.163.com/M/topic/detail/12450159
https://avg.163.com/topic/detail/12450130
https://avg.163.com/M/topic/detail/12450130
https://avg.163.com/topic/detail/12640399
https://avg.163.com/M/topic/detail/12640399
https://avg.163.com/topic/detail/12640397
https://avg.163.com/M/topic/detail/12640397
https://avg.163.com/topic/detail/12640395
https://avg.163.com/M/topic/detail/12640395
https://avg.163.com/topic/detail/12640383
https://avg.163.com/M/topic/detail/12640383
https://avg.163.com/topic/detail/12450121
https://avg.163.com/M/topic/detail/12450121
https://avg.163.com/topic/detail/12450138
https://avg.163.com/M/topic/detail/12450138
https://avg.163.com/topic/detail/12640375
https://avg.163.com/M/topic/detail/12640375
https://avg.163.com/topic/detail/12640374
https://avg.163.com/M/topic/detail/12640374
https://avg.163.com/topic/detail/12640373
https://avg.163.com/M/topic/detail/12640373
https://avg.163.com/topic/detail/12640372
https://avg.163.com/M/topic/detail/12640372
https://avg.163.com/topic/detail/12640371
https://avg.163.com/M/topic/detail/12640371
https://avg.163.com/topic/detail/12640370
https://avg.163.com/M/topic/detail/12640370
https://avg.163.com/topic/detail/12450122
https://avg.163.com/M/topic/detail/12450122
https://avg.163.com/topic/detail/12450113
https://avg.163.com/M/topic/detail/12450113
https://avg.163.com/topic/detail/12450108
https://avg.163.com/M/topic/detail/12450108
https://avg.163.com/topic/detail/12450124
https://avg.163.com/M/topic/detail/12450124
https://avg.163.com/topic/detail/12449897
https://avg.163.com/M/topic/detail/12449897
https://avg.163.com/topic/detail/12640364
https://avg.163.com/M/topic/detail/12640364
https://avg.163.com/topic/detail/12640362
https://avg.163.com/M/topic/detail/12640362
https://avg.163.com/topic/detail/12640363
https://avg.163.com/M/topic/detail/12640363
https://avg.163.com/topic/detail/12640360
https://avg.163.com/M/topic/detail/12640360
https://avg.163.com/topic/detail/12450123
https://avg.163.com/M/topic/detail/12450123
https://avg.163.com/topic/detail/12450097
https://avg.163.com/M/topic/detail/12450097
https://avg.163.com/topic/detail/12450109
https://avg.163.com/M/topic/detail/12450109
https://avg.163.com/topic/detail/12450107
https://avg.163.com/M/topic/detail/12450107
https://avg.163.com/topic/detail/12450101
https://avg.163.com/M/topic/detail/12450101
https://avg.163.com/topic/detail/12450141
https://avg.163.com/M/topic/detail/12450141
https://avg.163.com/topic/detail/12450104
https://avg.163.com/M/topic/detail/12450104
https://avg.163.com/topic/detail/12640344
https://avg.163.com/M/topic/detail/12640344
https://avg.163.com/topic/detail/12640342
https://avg.163.com/M/topic/detail/12640342
https://avg.163.com/topic/detail/12640340
https://avg.163.com/M/topic/detail/12640340
https://avg.163.com/topic/detail/12450095
https://avg.163.com/M/topic/detail/12450095
https://avg.163.com/topic/detail/12450100
https://avg.163.com/M/topic/detail/12450100
https://avg.163.com/topic/detail/12640334
https://avg.163.com/M/topic/detail/12640334
https://avg.163.com/topic/detail/12640335
https://avg.163.com/M/topic/detail/12640335
https://avg.163.com/topic/detail/12640330
https://avg.163.com/M/topic/detail/12640330
https://avg.163.com/topic/detail/12640325
https://avg.163.com/M/topic/detail/12640325
https://avg.163.com/topic/detail/12640321
https://avg.163.com/M/topic/detail/12640321
https://avg.163.com/topic/detail/12640324
https://avg.163.com/M/topic/detail/12640324
https://avg.163.com/topic/detail/12640317
https://avg.163.com/M/topic/detail/12640317
https://avg.163.com/topic/detail/12450078
https://avg.163.com/M/topic/detail/12450078
https://avg.163.com/topic/detail/12450075
https://avg.163.com/M/topic/detail/12450075
https://avg.163.com/topic/detail/12450089
https://avg.163.com/M/topic/detail/12450089
https://avg.163.com/topic/detail/12450079
https://avg.163.com/M/topic/detail/12450079
https://avg.163.com/topic/detail/12450094
https://avg.163.com/M/topic/detail/12450094
https://avg.163.com/topic/detail/12450076
https://avg.163.com/M/topic/detail/12450076
https://avg.163.com/topic/detail/12450070
https://avg.163.com/M/topic/detail/12450070
https://avg.163.com/topic/detail/12640313
https://avg.163.com/M/topic/detail/12640313
https://avg.163.com/topic/detail/12640314
https://avg.163.com/M/topic/detail/12640314
https://avg.163.com/topic/detail/12640308
https://avg.163.com/M/topic/detail/12640308
https://avg.163.com/topic/detail/12640312
https://avg.163.com/M/topic/detail/12640312
https://avg.163.com/topic/detail/12640310
https://avg.163.com/M/topic/detail/12640310
https://avg.163.com/topic/detail/12450069
https://avg.163.com/M/topic/detail/12450069

在函数或一个代码块内部声明的变量，称为局部变量。它们只能被函数内部或者代码块内部的语句使用。下面的实例使用了局部变量：

实例

#include <iostream> using namespace std; int main () { // 局部变量声明 int a, b; int c; // 实际初始化 a = 10; b = 20; c = a + b; cout << c; return 0; }

全局变量

在所有函数外部定义的变量（通常是在程序的头部），称为全局变量。全局变量的值在程序的整个生命周期内都是有效的。

全局变量可以被任何函数访问。也就是说，全局变量一旦声明，在整个程序中都是可用的。下面的实例使用了全局变量和局部变量：

实例

#include <iostream> using namespace std; // 全局变量声明 int g; int main () { // 局部变量声明 int a, b; // 实际初始化 a = 10; b = 20; g = a + b; cout << g; return 0; }

在程序中，局部变量和全局变量的名称可以相同，但是在函数内，局部变量的值会覆盖全局变量的值。下面是一个实例：

实例

#include <iostream> using namespace std; // 全局变量声明 int g = 20; int main () { // 局部变量声明 int g = 10; cout << g; return 0; }

当上面的代码被编译和执行时，它会产生下列结果：

10

初始化局部变量和全局变量

当局部变量被定义时，系统不会对其初始化，您必须自行对其初始化。定义全局变量时，系统会自动初始化为下列值：

转载自CSDN-专业IT技术社区

原文链接：https://blog.csdn.net/2601_95346943/article/details/158432663