c语言中和形式参数同名的情况

 

001、函数体内的变量名不可以和形参同名

a、

[root@PC1 test]# ls
test.c
[root@PC1 test]# cat test.c
#include <stdio.h>

int max(int a, int b)
{
        int k = 100;
        return a > b ? a:b;
}

int main(void)
{
        int x = 10, y = 30;

        printf("larger: %d\n", max(x,y));

        return 0;
}
[root@PC1 test]# gcc test.c -o kkk
[root@PC1 test]# ls
kkk  test.c
[root@PC1 test]# ./kkk
larger: 30

 

 

b、

[root@PC1 test]# ls
test.c
[root@PC1 test]# cat test.c
#include <stdio.h>

int max(int a, int b)
{
        int b = 100;     // 函数体内的变量名和形参同名导致无法编译
        return a > b ? a:b;
}

int main(void)
{
        int x = 10, y = 30;

        printf("larger: %d\n", max(x,y));

        return 0;
}
[root@PC1 test]# gcc test.c -o kkk
test.c: In function ‘max’:
test.c:5:13: error: ‘b’ redeclared as different kind of symbol
    5 |         int b = 100;
      |             ^
test.c:3:20: note: previous definition of ‘b’ with type ‘int’
    3 | int max(int a, int b)
      |                ~~~~^

 

002、函数调用时的实参可以和形参同名。

[root@PC1 test]# ls
test.c
[root@PC1 test]# cat test.c
#include <stdio.h>

int max(int a, int b)
{
        return a > b ? a : b;
}

int main(void)
{
        int a = 10, b = 50;

        printf("larger: %d\n", max(a,b));    // 函数调用的实参跟函数定义时的形参同名，对函数无影响

        return 0;
}
[root@PC1 test]# gcc test.c -o kkk
[root@PC1 test]# ls
kkk  test.c
[root@PC1 test]# ./kkk
larger: 50

 

。

 

003、不同函数的形参可以同名

test.c
[root@PC1 test]# cat test.c
#include <stdio.h>
int max2(int a, int b)
{
        return a > b ? a:b;
}
int max3(int a, int b, int c)    // 不同函数的形参可以是同名的， 比如这里的max2和max3函数的形参a和b
{
        int max = a; if(max < b) {max = b;}; if(max < c){max = c;};return max;
}
int main(void)
{
        int a, b, c;
        printf("a = "); scanf("%d", &a);printf("b = "); scanf("%d", &b);printf("c = "); scanf("%d", &c);
        printf("the large between a and b is %d\n", max2(a,b));
        printf("the largest among a, b, and c is %d\n", max3(a,b,c));return 0;
}
[root@PC1 test]# gcc test.c -o kkk
[root@PC1 test]# ls
kkk  test.c
[root@PC1 test]# ./kkk
a = 34
b = 546
c = 345
the large between a and b is 546
the largest among a, b, and c is 546
[root@PC1 test]# ./kkk
a = 35
b = 566
c = 3255
the large between a and b is 566
the largest among a, b, and c is 3255

 。