# 标准库stdlib.h函数itoa()

原型

```c
char *  itoa (int value, char * str, int base);
```

把整型数字转换成字符串存储在数组中。

参数

```bash
value: 一个整型
str: 字符数组
base: 进制
```

返回指向生成的以 null 结尾的字符串的指针，与参数`str`相同。这个函数未在 ANSI-C 中定义，也不是 C++ 的一部分，但受某些编译器支持。在某些情况下，符合标准的替代方案是sprintf。特别注意！！！非标准库函数，移植性差，在使用时应注意。

==我分别使用了GCC和MSVC2015编译器编译了一段实例，都发生错误，这个函数已经不被一般的编译器所支持，所以弃用该函数。==

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

//浮点结构
typedef struct  
{
	unsigned int nMant : 23; //尾数
	unsigned int nExp : 8; //指数
	unsigned int nSign : 1; //符号
} FP_SINGLE;

int main(int argc, char *argv[]) {
	char strBin[33] = { 0 };
	float f = 19.625;
	FP_SINGLE *p = (FP_SINGLE*)&f;

	itoa(p->nSign, strBin, 2);
	printf("Sign: %s\n", strBin);

	itoa(p->nExp, strBin, 2);
	printf("exp: %s\n", strBin);

	itoa(p->nMant, strBin, 2);
	printf("mant: %s\n", strBin);

	return 0;
}
```




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