char类型转换成int_char 转int

#include <stdio.h>
#include <string.h>

void CharToInt(int *dest, char *src, long len);

int main(void)
{ 
   
        unsigned char *str = "1121";
        int value, str_len;

        str_len = strlen(str);
        CharToInt(&value,str,str_len);
        printf("%d\n",value);
}
/*转换后数值的地址，传入的字符串，字符串长度*/
void CharToInt(int *dest, char *src, long len)
{ 
   
        int i;
        int value_temp = 0;

        for(i=0;i<len;i++)
        { 
   
                value_temp = value_temp*10 + (*(src+i)-'0');
        }
        *dest = value_temp;
}

/*运行*/
1121

#include <stdio.h>

#define HIGH 0
#define LOW 1

void CharToInt(int *, char *, long , int );

int main(void)
{ 
   
        unsigned char str[] = { 
   0x11,0x21};
        int value, str_len;

        str_len = sizeof(str);
        CharToInt(&value,str,str_len,HIGH);
        printf("%d\n",value);
}
/*转换后数值的地址，传入的字符串，字节个数，高或低字节在前*/
void CharToInt(int *dest, char *src, long len, int highlow)
{ 
   
        int i, j;
        int value_temp = 0;

        if(highlow == HIGH)
        { 
   
                j = len-1;
                for(i=0;i<len;i++)
                { 
   
                        value_temp |= ((*(src+i))&0xff)<<(8*j); 
                        j--;
                }
        }
        else
        { 
   
                for(i=0;i<len;i++)
                { 
   
                        value_temp |= ((*(src+i))&0xff)<<(8*i);
                }
        }
        *dest = value_temp;
}

/*运行*/
4385

#include <stdio.h>

union CharInt
{ 
   
        unsigned char str[2];
        short int value;
};

int main(void)
{ 
   
        union CharInt I;
        I.value = 0;
        I.str[1] = 0x11;
        I.str[0] = 0x21;

        printf("%d\n",I.value);
}

/*运行*/
4385