c++ 学习(值传递、引用传递、地址传递)
说明
- 值传递
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函数调用时,将实参的值传给形参 形参发生改变,不影响实参
- 引用传递
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函数调用时,相当于使用形参的名称作为实参的别名,指向同一片内存区域 形参发生变化时,影响实参
- 地址传递
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函数调用时,将实参的地址传给形参 形参地址对应的值发生变化时,影响实参
函数调用栈
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值传递 引用传递
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地址传递
函数实例
#include <iostream> using namespace std; // 指针传递 void swap3(int *a, int *b) { int temp = *a; *a = *b; *b = temp; cout << "swap3 function, value of a=" << *a << ";address is:" << a << endl; cout << "swap3 function, value of b=" << *b << ";address is:" << b << endl; } // 引用传递 void swap2(int &a, int &b) { int temp = a; a = b; b = temp; cout << "swap2 function, value of a=" << a << ";address is:" << &a << endl; cout << "swap2 function, value of b=" << b << ";address is:" << &b << endl; } // 值传递 void swap1(int a, int b) { int temp = a; a = b; b = temp; cout << "swap1 function, value of a=" << a << ";address is:" << &a << endl; cout << "swap1 function, value of b=" << b << ";address is:" << &b << endl; } int main(){ int a1 = 10; int b1 = 20; int a2 = 10; int b2 = 20; int a3 = 10; int b3 = 20; swap1(a1, b1); cout << "main function, value of a=" << a1 << ";address is:" << &a1 << endl; cout << "main function, value of b=" << b1 << ";address is:" << &b1 << endl << endl; swap2(a2, b2); cout << "main function, value of a=" << a2 << ";address is:" << &a2 << endl; cout << "main function, value of b=" << b2 << ";address is:" << &b2 << endl << endl; swap3(&a3, &b3); cout << "main function, value of a=" << a3 << ";address is:" << &a3 << endl; cout << "main function, value of b=" << b3 << ";address is:" << &b3 << endl << endl; }
输出结果
swap1 function, value of a=20;address is:0x61fee0 swap1 function, value of b=10;address is:0x61fee4 main function, value of a=10;address is:0x61ff0c main function, value of b=20;address is:0x61ff08 swap2 function, value of a=20;address is:0x61ff04 swap2 function, value of b=10;address is:0x61ff00 main function, value of a=20;address is:0x61ff04 main function, value of b=10;address is:0x61ff00 swap3 function, value of a=20;address is:0x61fefc swap3 function, value of b=10;address is:0x61fef8 main function, value of a=20;address is:0x61fefc main function, value of b=10;address is:0x61fef8
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