# 标准库stdlib.h函数malloc()

**原型**

```c
void * malloc(size_t size);
```

**说明**

分配一个size字节（Bytes）的内存，返回一个指向该内存块开始处的指针。新分配的内存块的内容未初始化，剩余的值不确定。如果 size 为零，则返回值取决于特定的库实现（它可能是也可能不是空指针），但不应取消引用返回的指针。

**实例**

```c
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[]){
    int i, n;
    char *buffer;
    
    printf("How long do you want the string? ");
    scanf("%d", &i);
    
    buffer = (char *)malloc(i*1);
    if(buffer==NULL) exit(1);
    
    for(n=0; n<i; n++){
        buffer[n] = rand()%26+'a';
    }
    buffer[i]='\0';
    
    printf("Random string: %s\n", buffer);
    free(buffer);
    return 0;
}
```


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