C语言——如何将字符型数组转换为int型（解法集合）

1.常见的解决方案

知识点备注:  '1' - '0' = 1

具体事例分析:

char str[10] = "12345";

'1' - '0' = 1;

1 * 10 + '2' - '0' = 12;

12 * 10 + '3' - '0' = 123;

123 * 10 + '4' - '0' = 1234;

1234 * 10 + '5' - '0' = 12345;

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

int main()
{
    char str[10] = "123456";
    int num = 0;

    const char* ptr = str;
    while(*ptr)
    {
        num *= 10;
        num += *ptr - '0';
        ptr++;
    }
    printf("num = %d\n",num);
    
    return 0;
}

2.使用atoi函数

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

int main()
{
    char *a = "1234";
    int n = atoi(a);
    printf("%d\n",n);

    return 0;
}

3.使用sscanf函数

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

int main()
{

    char *a = "1234";
    sscanf(a,"%d",&n);
    printf("%d\n",n);

    return 0;
}