# 标准库stdlib.h函数atoi()

**原型**

```c
int atoi(const char * str);
```

**说明**

转换字符串为整型，这个函数从非空白字符串开始直到第一个空格位置，可以包含其他字符，但是如果第一个字符如果是非数字字母，还是会返回0值。如果一个数字字符都没有，那么返回0值，当然如果字符串中间有浮点数也会返回0值。

**实例**

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

int main(){
    int i;
    char buffer[256];
    printf("Input: ");
    fgets(buffer, 256, stdin);
    i = atoi(buffer);
    printf("The value is %d.\n", i);
    return 0;
}
```




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